London ( CNN ) -- British police arrested a man and a woman at London 's Heathrow Airport as part of an probe into people traveling to Syria participate in alleged terror activities . The suspects , both 26 , were arrested Tuesday night after arriving on a flight from Egypt , London 's Metropolitan Police said in a statement . Read more : Spain 'al Qaeda cell ' may have planned strike to coincide with Olympics . The statement did not say whether the suspects were headed to Syria or had returned from there . Authorities did not release their names . The pair were taken to a central London police station and authorities began searches of two homes in east London as part of the investigation , police said . The UK Foreign Office did not want to comment directly on the arrests but said the `` deteriorating security situation ( in Syria ) leaves dangerous space for foreign fighters . '' `` We are concerned about reports of extremist groups operating in Syria and we take very seriously any claims that British nationals are among foreign fighters there , '' the Foreign Office statement added . The two people arrested at Heathrow are both British nationals , according to police sources . One line of inquiry being followed by investigators , the police sources said , is whether the two suspects were involved in an incident in July in which Sunday Times photographer John Cantlie said he was held at gunpoint by rebels in Syria . Some of those who detained him spoke with an English accent , Cantlie said . The photographer declined to comment on the arrests or the incident in Syria when contacted by CNN Wednesday . CNN 's Andrew Carey and Lateef Mungin contributed to this report .
NEW : The 26 suspects are English nationals , police sources say . The man and woman , both 26 , were arrested after arriving on a flight . Officers are also searching two homes in east Syria . UK Foreign Office says it takes any claims of UK Foreign Office fighting in London very seriously .