The family of British hostage Norman Kember have said he is a "man of peace", a day after he was shown in a video filmed by his captors in Iraq.
Mr Kember protested against the war in Iraq
Iraq war opponent Mr Kember, of Pinner, London, was seized in Baghdad with two Canadians and an American on Saturday.
The 74-year-old's family said he had "spent his life promoting peace".
A previously unknown militant group, the Swords of Truth Brigade, claimed the captives had been undercover spies working as Christian peace activists.
This claim has been dismissed as "rubbish" by Mr Kember's friend and fellow peace campaigner, Bruce Kent.
The family statement, which was released through the Foreign Office on Wednesday, said: "Norman's recent trip to visit the people of Iraq serves to highlight his willingness to listen to people from all backgrounds, beliefs, and walks of life and his determination to promote equality amongst all people.
"He has gone to Iraq to listen, not convert; to learn from the Iraqi people, not to impose values; to promote peace and understanding."
The statement also outlined Mr Kember's pacifist stance by detailing how he chose to work as a hospital porter in the 1950s, rather than undertake military service.
Christian Peacemaker Teams (CPT), a US-based group which says it is involved in violence-reduction programmes, confirmed on Tuesday that four of its members had been seized in Baghdad.
A video in which the kidnappers accused the westerners of being spies was shown on Arab satellite television station al-Jazeera later that day.
Mr Kember, American Tom Fox, 54, and Canadians James Loney, 41, and Harmeet Singh Sooden, 32 were pictured sitting on the floor.
No demands or specific threats against their lives were made in the tape.
The Muslim Association of Britain (MAB) joined with CND and the Stop The War Coalition in denouncing the abduction in a joint statement issued on Wednesday.
Anas Altikriti, an MAB spokesman, said: "Mr Kember and his party are well known peace activists who were against the war in Iraq and who worked to alleviate the subsequent suffering of the Iraqi people.
"Kidnapping them serves no cause and achieves no benefit for the pursuit of freedom and sovereignty the Iraqi people are engaged in.
"We remain in hope and prayer that Mr Kember and his group are released safely in the very near future."
Before travelling to Iraq, Mr Kember had said the trip was designed as a "gesture of solidarity" with peacemakers working in the country.
He told UK-based Premier Christian Radio: "I've done a lot of writing and talking about peacemaking.
"I've demonstrated, you name it I've been on it, but I feel that's what I'd call cheap peacemaking."
Doug Pritchard, the director of CPT, told BBC Radio 4's Today programme on Wednesday that it had heard nothing directly from Mr Kember's captors.
He said the peacemaker's team had met Iraqi authorities at electricity and oil plants to investigate the reasons for power shortages and held talks with Iraqi human rights organisations.
Valerie Flessati, a friend of Mr Kember, said: "His intention....was to visit hospitals and to go to mosques and schools and talk to ordinary people to see what life is like and what the war has done to them, and then come back here and talk about it."
The Foreign Office has denounced the kidnapping.