text: Karma Khayat and her TV station al-Jadeed are accused of contempt of court for revealing details about witnesses.
  They deny any wrongdoing, and say they are fighting for freedom of speech.
  The five men accused of killing Mr Hariri remain in hiding, and are being tried by the tribunal in absentia.
  Mr Hariri was killed along with 21 others when his motorcade was hit by a massive bomb blast in the Lebanese capital Beirut on 14 February 2005.
  The Special Tribunal for Lebanon (STL) was set up by the United Nations to try those responsible for the killings. The five suspects still at large have been linked to the militant Shia Islamist movement, Hezbollah.
  A few minutes after opening on Thursday, the tribunal went into private session, the BBC's Anna Holligan reports from The Hague.
  It followed accusations from the defence that the prosecution had revealed new evidence just a day before the hearing, and was thus attempting a "trial by ambush", our correspondent adds.
  Prosecutors in the case say Ms Khayat and al-Jadeed published a list of witnesses' names, which undermined the confidence of those witnesses because they had been promised anonymity.
  Ms Khayat says the list she published was redacted, which made it impossible to identify any witnesses but showed the tribunal was vulnerable to leaks. The full list of witnesses was later published by other parties unknown, she asserts.
  Ms Khayat accused the court of attempting to silence the Lebanese media "in order not to criticise the tribunal in future".
  "I believe my role in court is not to defend Karma Khayat and not to defend al-Jadeed; there's nothing to defend, we have a very strong case," she told the BBC.
  "I am there to defend freedom of speech and freedom of press," she added.
target: A Lebanese journalist has become the first person to take the stand at the UN-backed tribunal at The Hague investigating the assassination of former Prime Minister Rafik Hariri.