Rowan Williams, the Archbishop of Canterbury, and Cardinal Cormac Murphy-O'Connor, the leader of the Roman Catholic church in England and Wales, issued a rare joint statement last night, warning that doubts still persisted about the moral legitimacy of a war in Iraq.
Although stopping short of condemning military action, the church leaders said war was "a deeply disturbing prospect; one that can never be contemplated without a sense of failure and regret that other means have not prevailed, and deep disquiet about all that may come in its train".
They promised to pray for the leaders carrying the responsibility of making the ultimate decisions, and for "all those who would find themselves caught up directly or indirectly in a war".
They called on them to operate through the United Nations on continuing weapon inspections to render the trauma and tragedy of war unnecessary. And they warned of the "unpredictable humanitarian and political consequences" of war.
The archbishops' joint statement came after a week in which Prime Minister Tony Blair had repeatedly argued what he called "the moral case" for removing Saddam Hussein.
While acknowledging that innocent Iraqis would die in any military action, Mr Blair said it would be "inhumane" to allow President Saddam to remain in power, because of the suffering he would cause his people.
The archbishops said: "We recognise that the moral alternative to military action cannot be inaction, passivity, appeasement or indifference.
"It is vital therefore that all sides in this crisis engage, through the United Nations - fully and urgently - in a process, including continued weapons inspections, that could and should render the trauma and tragedy of war unnecessary. We strongly urge the government of Iraq to demonstrate forthwith its unequivocal compliance with UN resolutions on weapons of mass destruction.
"The season of Lent is now approaching, a time when all Christian traditions encourage us to examine ourselves honestly, to acknowledge our shortcomings and to seek reconciliation with God.
"We must hope and pray that with God's guidance an outcome which brings peace with justice to Iraq and the Middle East may yet be found."