VATICAN CITY: Pope John Paul cautioned world leaders on Wednesday against obtaining peace through the use of military force, a day after the US president defended his decision to invade Iraq.

"The world ardently aspires towards peace, needs peace, today as yesterday, but often searches for it by improper means, sometimes even through recourse to violence."

"In such conditions, man lives with a heart troubled by fear and uncertainty," the pontiff said during his weekly general audience at the Vatican.

Mr Bush used his annual address to defend his decision to invade Iraq and said the United States would never seek permission to wage war in self-defence. "America will never seek a permission slip to defend the security of our country," said Mr Bush.

The pope had waged a lengthy diplomatic campaign to avert the invasion of Iraq. He will get an opportunity to restate his steadfast opposition to the conflict in talks with US Vice President Dick Cheney slated for Tuesday during a visit by Mr Cheney to Italy and the Vatican.

During his audience on Wednesday, John Paul called on all Christians "to together make a decisive contribution so that humanity can overcome the reasons for division and conflicts".

"Be authentic workers for peace among those with whom we live." He said for that it was necessary to promote Christian unity. He invited Christians "not to be discouraged when faced with old and new difficulties" on the path to reunification, "but to tackle them with patience and understanding".

The pope appeared in relatively good form during the audience, which was attended by some five thousand pilgrims. At its conclusion, he prayed for leaders and officials from international organizations working for peace as well as for those "who suffer because of war, injustice and oppression".

In keeping with a Vatican tradition on the feast day of Saint Agnes, he blessed several lambs whose wool will be used to make the "pallium", the stole worn by archbishops as a sign of their communion with the pope. -AFP