An anti-war envoy is continuing to meet Sunni Muslim groups in Iraq in a bid to secure the release of kidnapped Briton Norman Kember and three other men.
Anas Altikriti said he realised his mission was not an easy one
Some have already called for their release and Iraq's largest Sunni party, the Iraqi Islamic party, said it tarnished the image of Islam.
"The kidnapping will have a grave negative effect among those who call for ending occupation," it added.
Envoy Anas Altikriti was sent to Baghdad by peace and Muslim groups.
His visit follows the screening of a video showing the peace campaigners in captivity and threats by their captors to kill them if Iraqis were not released from prison by Thursday.
Newspapers, meanwhile, have published appeals from other Islamic groups, pointing out the fact that the four hostages were working for the benefit of the Iraqi people.
The Iraqi Islamic Party's statement said: "Continuing to hold them will give those who support the war against our country a chance to say that Iraqis don't make a difference between those who support them and those who are against them".
It added: "There are some who are trying to tarnish the clear white image of our religion."
Mr Altikriti, who was sent to Iraq by the Muslim Association of Britain, Stop the War and CND, has given interviews to the local media.
He told the BBC as an Iraqi he appreciated the country's situation.
"It's a very very dangerous situation, there can be no question about it, but I come as an Iraqi, someone born in Iraq, and therefore, I'm at home.
"And therefore I'm joining in, riding the same boat that 23, 24 million Iraqis have been in for the past two-and-a-half years and the very same situation that Mr Kember - quite nobly, him and his colleagues - accepted to enter themselves, in order to carry out this noble mission."
He told the BBC he realised his mission was not an easy one.
"I think back to the Kenneth Bigley saga, the Margaret Hassan saga, and I dread what could happen.
"But I also look back to the two French aid workers, the Italian journalists, to the Romanians, and I think 'yes, it could happen'."
Iraq war opponent Mr Kember, 74, of London, was seized in Baghdad last week.
Mr Altikriti said he had no hidden agenda and it was "too delicate a situation to be partisan".
Mr Kember has been held since last Saturday
"So I'm taking extreme care to be seen as who I really am and that is neutral. I don't have a particular interest at this stage of time, apart from getting Mr Kember released," he said.
In a BBC interview, the Muslim Association of Britain spokesman Ihtisham Hibatullah said he was hopeful Mr Altikriti would be able to influence the kidnappers.
"This is the unknown territory we are going into but we have hope once Anas started speaking to the local community leader as he has already done through al-Jazeera television last night.
"What we are trying to do is influence their minds to say that he's a true friend of Iraq and a peace campaigner," he said.
Mr Kember has been held since Saturday along with three other peace activists - American Tom Fox, 54, and Canadians James Loney, 41, and Harmeet Singh Sooden, 32.
Mr Kember and Mr Fox were shown on the latest video calling for the kidnappers' demands to be met, al-Jazeera said.
A previously unknown militant group, the Swords of Truth Brigade, claimed the captives were undercover spies working as Christian peace activists.
Mr Kember had been working with a Canadian-based organisation, Christian Peacemaker Teams.
A total of 238 foreign nationals were kidnapped in Iraq between May 2003 and 20 November 2005, with about one in five killed, according to an index compiled by the Brookings Institution in Washington.
It is thought that thousands of Iraqis were kidnapped over the same period.