The family of Norman Kember, the British hostage being held in Iraq, will mark Christmas without him by placing an advert in Iraqi newspapers and radio programmes calling for his release.
There has been no news of the 74-year-old peace campaigner from Pinner, north-west London, since the 10 December deadline his captors set for his execution.
Mr Kember's wife, Pat, 72, has left the home the couple have shared for three decades to spend Christmas elsewhere with family - thought to be her two daughters and three-year-old grandson. A friend said she was "very anxious" and that "nobody is confident" about his fate.
Others said a "cautious optimism" had emerged that Mr Kember might be freed as a result of appeals from across the Muslim world, including one from the cleric Abu Qatada, who is in custody at Belmarsh jail in London under anti-terror legislation.
The Rev Alan Betteridge, who met Mr Kember on a peace campaign 40 years ago, said that releasing the hostages "would be a gesture of reconciliation and progress, rather than antagonism and revenge". He added: "We remain optimistic that no news is good news and we are praying for his safe return this Christmas."
Mr Kember was seized by the Swords of Righteousness Brigade in Baghdad on 26 November with James Loney, 41, and Harmeet Sooden, 32, from Canada, and an American, Tom Fox, 54. The four were in Iraq as members of Christian Peacemaker Team, a Canadian-based international peace group.
A Foreign Office spokesman said there were no new developments. Friends and supporters of Mr Kember will hold a prayer vigil in Trafalgar Square in London at 3pm on 29 December, 33 days after he was abducted. "We must not forget them because of this ongoing silence," said Pat Gaffney, general secretary of the organiser, Pax Christi.