Pope John Paul II has urged Tony Blair to make "every effort" to avoid going to war with Iraq.
Mr Blair and the Pope had a private discussion
The UK prime minister had a private audience with the 82-year-old pontiff, a staunch opponent of conflict, at the Vatican on Saturday.
In a statement issued after the 15-minute meeting, the Vatican said: "The Holy Father hoped that, in finding a solution to the grave situation in Iraq, every effort must be made to avoid new divisions in the world."
Use the resources
offered by international law to avoid the tragedy of a war
The Pope "reiterated the need for all parties to the Iraqi
crisis to collaborate with the United Nations".
It urged the use of international law "to avoid the tragedy of a war which
according to many people is still avoidable".
The Pope also highlighted his concerns for the
"humanitarian situation of the Iraqi people, already desperately deprived by long years of embargo."
The BBC's Brian Barron, at the Vatican, said he thought Mr Blair would consider the visit a political and personal success.
"Mr Blair is keen to be seen showing that he's going the extra mile, talking to the Pope who is, no question about it, the world's most revered public figure with an anti-war stance."
The prime minister's wife Cherie, a Catholic, and some of their children met the pontiff for a further 15 minutes after the formal audience took place.
Let me just make one thing also plain - we do not want war
Mr Blair is an Anglican, but the Blair children have been brought up in her faith and they regularly attend a Roman Catholic church together as a family.
Earlier this week, the Archbishops of Westminster and Canterbury issued a joint statement calling for continued weapons inspections which, they said, could avert the need for military action.
The Pope has made clear his opposition to war and recently met the Iraqi deputy prime minister, Tariq Aziz, and United Nations general secretary Kofi Annan.
And Italian newspapers had quoted Vatican sources as saying the Pope was reluctant to meet Mr Blair because of his readiness to use force against Saddam Hussein.
Last month he called for diplomatic efforts to be stepped up and said a military conflict would harm ordinary Iraqis, "already sorely tried" by sanctions imposed after the Gulf War.
Italy's Berlusconi and Blair are unlikely allies over Iraq
After meeting Saddam Hussein last weekend, the Pope's envoy said that peace was possible and that the Iraqi leader had been "very open to dialogue".
Speaking in Rome after an earlier meeting with Italian Prime Minister Silvio Berlusconi, Mr Blair said: "Let me just make one thing also plain - we do not want war, no
one wants war."
He added: "What the words of His Holiness the Pope have described... is the reluctance of people to go to war except as a last resort. That is our position."