Archbishop of Canterbury Dr Rowan Williams has said that the killing of an unarmed Osama Bin Laden by US special forces makes him feel "uncomfortable".
He also commented that "it is important that justice is seen to be observed" in a situation like this, involving a "war criminal".
Dr Williams' words will be seen as guarded questioning - if not quite criticism - of the US action in assassinating, rather than arresting, the man who is seen as the key figure in the horrific attacks on the World Trade Centre in New York and other targets on 11 September 2001, which claimed nearly 3,000 lives.
At a press conference on domestic church issues, the Archbishop, who is the most senior cleric in the Church of England and the spiritual leader of the 77-million strong world wide Anglican Communion, was posed specific questions about the killing of the Al Qaida leader.
Dr Williams was asked: "Do you believe that the killing of Osama Bin Laden is justice for the 9/11 attacks and indeed other attacks? And was the US morally justified in shooting him even though he was unarmed as the White House now admits?"
He responded: "I think that 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, in those circumstances.
"I think it is also true that the different versions of events that have emerged in recent days have not done a great deal to help here.
"I don't know the full details anymore than anyone else does but I do believe that in such circumstance when we are faced with someone who was manifestly a 'war criminal' as you might say in terms of the atrocities inflicted, it is important that justice is seen to be observed," concluded the Archbishop.