The Archbishop of Canterbury today said the killing of an unarmed Osama bin Laden by US special forces left him with a "very uncomfortable feeling".
Dr Rowan Williams, the leader of the Anglican church, also criticised the way in which the Obama administration has appeared to change its account of the raid.
Asked about the moral justification of the al-Qa'ida mastermind's death in Pakistan, he said: "I think the killing of an unarmed man is always going to leave a very uncomfortable feeling because it doesn't look as if justice is seen to be done."
He added: "I think it's also true that the different versions of events that have emerged in recent days have not done a great deal to help.
"I don't know the full details any more than anyone else does. But I do believe that in such circumstances, when we are faced with someone who was manifestly a war criminal in terms of the atrocities inflicted, it is important that justice is seen to be served."
Dr Williams was speaking at a press briefing at Lambeth Palace, London, announcing the appointment of two clergy as "flying bishops".
His comments came as a senior US defence official admitted that only one of the five people killed in the operation was armed and fired shots.
Briefings earlier in the week by White House and Pentagon staff had portrayed the raid as involving prolonged and fierce firefights, with initial reports that bin Laden had fired a weapon.
The unnamed official said the story had become clearer as the Navy Seal team were debriefed.
Today President Barack Obama flew to New York ahead of a visit to Ground Zero, where he will meet relatives of those who died in the World Trade Centre attacks and lay a wreath. He is not expected to make a speech.
Mr Obama yesterday defended his decision not to release a photograph of Bin Laden's corpse, saying the images could become a "national security risk" and incite violence.
Eric Holder, the US Attorney General, told the Senate Judiciary Committee the killing of bin Laden was "lawful" and "justified as an act of national self defence".
"If he had surrendered, attempted to surrender, I think we should obviously have accepted that, but there was no indication that he wanted to do that and therefore his killing was appropriate," he said.
He said the US expected to add more names to its terrorism watch-list as a result of data seized in the raid.
In comments largely for domestic consumption, the Pakistani foreign secretary has warned America of "disastrous consequences" if it carries out any other unilateral raids against suspected terrorists in its country.
"The Pakistan security forces are neither incompetent nor negligent about their sacred duty to protect Pakistan," he said.
He said the army scrambled two F-16 fighter jets when it was aware that foreign helicopters were hovering over the city of Abbottabad, but they apparently did not reach the American forces in time.
He said there would be no investigation into how the Pakistani security services failed to spot bin Laden's hideaway - a large house near a military academy in a garrison town.
Dr Williams is the latest religious leader to comment on the ethics of the killing of bin Laden.
On Monday Father Federico Lombardi, a Vatican spokesman, said that while Christians "do not rejoice" over a death, it serves to remind them of "each person's responsibility before God and men".
"Osama bin Laden, as everyone knows, had the grave responsibility of having spread division and hate among people, causing the deaths of an innumerable number of people and exploiting religion for these purposes," he said.
Farooq Murad, the secretary general of the Muslim Council of Britain said on Monday the killing of bin Laden was "unfortunate" in denying the families of his victims the chance to see him brought to justice in a courtroom, but added: "Few will mourn the reported death of Osama bin Laden, least of all Muslims."
"The actions of his movement, which have no basis in the teachings of Islam, have led to the pursuit of unjust wars and untold suffering."
"Al-Qa'ida ability to sow discord and mistrust between Muslims and others has caused untold damage."
A spokesman for Archbishop Vincent Nichols, the head of the Catholic Church in England and Wales, said he would not be commenting on the killing.
Anjem Choudary, the leader of the outlawed extremist group al-Muhajiroun and member of the "poppy burning" group Muslims Against Crusades has called for a protest outside the US Embassy in Grosvenor Square, London, tomorrow afternoon.
The US raid had made a 7/7-style attack on Britain more likely, he said.