Media playback is unsupported on your device Media caption David Miranda: "I was kept in a room with six agents... asking me about everything." 
 
 Pressure is mounting on police to justify the detention of a journalist's partner under terror laws. 
 
 Senior politicians and an independent reviewer have said police must explain why David Miranda was detained for nine hours at Heathrow Airport. 
 
 Mr Miranda's partner is a journalist who published documents leaked by US whistleblower Edward Snowden. 
 
 Police have not said why Mr Miranda was held, but he said he was kept in a room and quizzed by "six agents". 
 
 Keith Vaz, chairman of the Home Affairs Select Committee, and shadow home secretary Yvette Cooper said police must explain why terrorism powers were used. 
 
 Brazil's foreign minister Antonio Patriota said he would call his UK counterpart William Hague to tell him the detention of Mr Miranda - a Brazilian national - was "not justifiable" and ask him to ensure it "won't happen again". 
 
 Media playback is unsupported on your device Media caption Neil Wallis, former executive editor, News of the World: "This is an appalling, blatant breach of press freedom" 
 
 Questions 'about everything' 
 
 Mr Miranda, 28, was held at Heathrow on Sunday on his way from Berlin to Rio de Janeiro, where he lives with his partner, Guardian journalist Glenn Greenwald. 
 
 "I remained in a room, there were six different agents coming and going, talking to me," Mr Miranda said. 
 
 "They asked questions about my entire life, about everything. 
 
 "They took my computer, video game, mobile phone, my memory cards, everything." 
 
 In Germany, Mr Miranda had been staying with US film-maker Laura Poitras, who has also been working on the Snowden files with Mr Greenwald and the Guardian, according to the newspaper. 
 
 Media playback is unsupported on your device Media caption Keith Vaz concerned about use of anti-terror laws 
 
 His flights were being paid for by the Guardian. A spokesman said he was not an employee of the newspaper but "often assists" with Mr Greenwald's work. 
 
 Mr Miranda was detained under schedule 7 of the Terrorism Act 2000. This allows police to hold someone at an airport for up to nine hours for questioning about whether they have been involved with acts of terrorism. 
 
 Anyone detained must "give the examining officer any information in his possession which the officer requests". Any property seized must be returned after seven days. 
 
 The Independent Reviewer of Terrorism Legislation, David Anderson QC, said it was very unusual for someone to be held for the full nine hours, and he wanted to "get to the bottom" of what had happened. 
 
 He said he had asked the Home Office and Scotland Yard for a full briefing. 
 
 'Bullying' 
 
 The Guardian said it was "dismayed" by the detention and was "urgently seeking clarification from the British authorities" as to why it had happened. 
 
 Analysis The stopping of David Miranda was highly unusual and will be just as controversial. These powers are often used to have a look at an individual heading in or out of the country to see if there is any evidence linking them to terrorism. That may involve questioning and a search of their belongings. In this case the search will likely be the key aspect. Police may well have been looking for any classified information originating from British and American intelligence and obtained by Edward Snowden. But this was not a random stop by a policeman on the ground. So who wanted him searched? Was it British intelligence? Or could it have been a request from the US? That's something it has denied although it won't stop questions. Another controversy will be over the stretching of counter-terrorism powers for something which doesn't look like it has anything to do with terrorism. Powers are often justified on the basis of stopping terrorist attacks. But what will the reaction be when they are used for something else? Add to this the fact the Brazilian government is clearly unhappy and that Glenn Greenwald says he will now go after British intelligence more aggressively in his journalism and you have to wonder if the person who made the decision might just be wondering if it was worth it. 
 
 The Metropolitan Police confirmed a 28-year-old man was held from 08:05 BST until 17:00 BST on Sunday under schedule 7 and was not arrested. 
 
 According to the Home Office, more than 97% of examinations under schedule 7 last less than an hour. 
 
 Mr Greenwald said the British authorities' actions in holding Mr Miranda amounted to "bullying" and linked it to his writing about Mr Snowden's revelations concerning the US National Security Agency (NSA). 
 
 He said it was "clearly intended to send a message of intimidation to those of us who have been reporting on the NSA and [UK intelligence agency] GCHQ". 
 
 He told the BBC police did not ask Mr Miranda "a single question" about terrorism but instead asked about what "Guardian journalists were doing on the NSA stories". 
 
 Mr Greenwald said he would respond by writing reports "much more aggressively than before". 
 
 "I have lots of documents about the way the secret services operate in England," he said. 
 
 "I think they are going to regret what they did." 
 
 'Extraordinary' 
 
 Mr Snowden, who has been granted temporary asylum in Russia, leaked details of extensive internet and phone surveillance by American intelligence services. 
 
 According to the Guardian, he passed "thousands of files" to Mr Greenwald, who has written a series of stories about surveillance by US and UK authorities. 
 
 Mr Vaz said police must "of course" question people if they have "concerns" about what they are doing in the UK. 
 
 Media playback is unsupported on your device Media caption Julian Assange tells Radio 4's PM programme that the detention was "an attack on journalism" 
 
 "What is extraordinary is they knew he was the partner [of Mr Greenwald] and therefore it is clear not only people who are directly involved are being sought but also the partners of those involved," he said. 
 
 "Bearing in mind it is a new use of terrorism legislation to detain someone in these circumstances... I will write to the police to ask for the justification of the use of terrorism legislation - they may have a perfectly reasonable explanation." 
 
 Ms Cooper said the situation must be "investigated and clarified urgently", adding: "The public support for these powers must not be endangered by a perception of misuse." 
 
 In a statement, the Liberal Democrats said police should use schedule 7 powers "proportionately and for good reason". 
 
 Journalism 'not terrorism' 
 
 Dr David Lowe, a former counter-terrorist detective, said the length of the detention might be explained by the "volume of documentation" carried by Mr Miranda. 
 
 He said the amount of information revealed by Mr Snowden to the Guardian was not yet known, but police might have kept Mr Miranda for the full nine hours allowed because they had lots of data to go through. 
 
 Dr Lowe also said Mr Miranda might have been targeted because of the "top secret" information police thought he was carrying, rather than because of his relationship with Mr Greenwald. 
 
 But journalists' groups have accused authorities of misusing terrorism laws. 
 
 Bob Satchwell, of the Society of Editors, said the incident was "another example of the dangerous tendency" for authorities to "assume that journalists are bad when in fact they play an important part in any democracy." 
 
 He added: "Journalism may be embarrassing and annoying for governments but it is not terrorism." ||||| RIO DE JANEIRO The journalist who first published secrets leaked by fugitive former U.S. intelligence agency contractor Edward Snowden vowed on Monday to publish more documents and said Britain will "regret" detaining his partner for nine hours. 
 
 British authorities used anti-terrorism laws on Sunday to detain David Miranda, partner of U.S. journalist Glenn Greenwald, as he passed through London's Heathrow airport. 
 
 Miranda, 28, a Brazilian citizen, said he was questioned for nine hours before being released without charge, minus his laptop, cellphone and memory sticks, which were seized. 
 
 Greenwald, a columnist for Britain's Guardian newspaper who is based in Brazil, said the detention was an attempt to intimidate him and stop him from publishing more secrets leaked by Snowden on U.S. surveillance of global internet communications. 
 
 Snowden, who has been granted asylum by Russia, gave Greenwald from 15,000 to 20,000 documents with details of the U.S. National Security Agency's surveillance programs. 
 
 Asked by a reporter if the detention of his partner would deter him from future reporting, Greenwald said the opposite would happen. 
 
 "I will be far more aggressive in my reporting from now. I am going to publish many more documents. I am going to publish things on England, too. I have many documents on England's spy system. I think they will be sorry for what they did," Greenwald, speaking in Portuguese, told reporters at Rio de Janeiro's airport where he met Miranda upon his return to Brazil. 
 
 Greenwald said in a subsequent email to Reuters that the Portuguese word "arrepender" should have been translated as "come to regret" not "be sorry for." 
 
 "I was asked what the outcome would be for the UK, and I said they'd come to regret this because of the world reaction, how it made them look, and how it will embolden me - not that I would start publishing documents as punishment or revenge that I wouldn't otherwise have published," he said in the email. 
 
 Miranda told reporters that six British agents questioned him about all aspects of his life during his detention in a room at Heathrow airport. 
 
 Brazil complained about the "unjustified" detention of Miranda under a British law used for suspects of terrorism. 
 
 Brazilian Foreign Minister Antonio Patriota called his British counterpart, William Hague, on Monday to express his concern. They agreed their governments would remain in contact over the incident, Britain's ambassador in Brasilia, Alex Ellis, said in a statement. 
 
 Many Brazilians are still upset with Britain's anti-terrorism policies because of the death of Brazilian electrician Jean Charles de Menezes, who was mistaken for a suspect in a bombing attempt in 2005. Menezes was shot seven times in the head by police on board an underground train at a London station. 
 
 Greenwald met with Snowden in June in Hong Kong, from where he published the first of many reports that rattled the U.S. intelligence community by disclosing the extent of surveillance by the NSA on telephone and internet communications. 
 
 Snowden faces criminal charges in the United States after leaking documents disclosing the previously secret U.S. internet and telephone surveillance programs. Russia rejected American pleas to send Snowden back to the United States for trial, instead granting him a year's asylum on August 1. 
 
 The White House said on Monday that U.S. officials did not ask the British government to question Greenwald's partner, though British authorities did give their U.S. counterparts a "heads up" before detaining Miranda. 
 
 Brazil, whose president, Dilma Rousseff, is scheduled to make a state visit to Washington in October, declined to consider an asylum request from Snowden. But some politicians angered by the disclosure of NSA surveillance of internet communications of Brazilians proposed granting him asylum in Brazil. 
 
 (Reporting by Pedro Fonseca; Writing by Anthony Boadle; Editing by Brian Winter and Eric Beech)
– Well, now the UK has gone and gotten itself on Glenn Greenwald's bad list. The Guardian journalist behind the Edward Snowden-NSA leaks story told reporters that after his partner was detained for nine hours at London's Heathrow airport, he plans to be "far more aggressive" in his reporting, Reuters reports. "I am going to publish things on England, too. I have many documents on England's spy system. I think they will be sorry for what they did," he said. Greenwald was at the Rio de Janeiro airport at the time to meet partner David Miranda upon his return to Brazil, where they both live. Brazil's government released a statement calling Miranda's detention unjustified, the Guardian also wants answers, and now even lawmakers in the UK are calling for an explanation from police as to why Miranda was held, the BBC reports. The Independent Reviewer of Terrorism Legislation says it's rare for anyone to be held for so long under schedule 7 of the Terrorism Act 2000, which allows police to detain someone at an airport for as long as nine hours to question them about links to terrorism. But "they never asked him about a single question at all about terrorism or anything relating to a terrorist organization," Greenwald says. "They spent the entire day asking about the reporting I was doing and other Guardian journalists were doing on the NSA stories."