After days of behind-the-scenes negotiations, ambassadors from all the Nato countries plus Russia and Yugoslavia have been summoned to a meeting at the Vatican on Tuesday afternoon.

Church officials say the Pope wants to see an end to fighting and the re-opening of diplomatic channels.

Our correspondent in Rome says the Pope is extremely concerned about the effects of continued Nato bombing, and believes his views are shared by public opinion in many Nato countries.

The Pope, a Slav, is conscious of the complex religious and historical causes of previous strife in the Balkans this century.

Religious leaders join call

Other religious leaders have been lining up to join the call for a halt to the Nato air strikes.

The Archbishop of Canterbury, leader of the Church of England, has called for a return to the negotiating table while religious leaders from across the Orthodox world have condemned the action against their fellow Serbian Orthodox.

The World Council of Churches, with over 300 member churches, has published a letter to UN Secretary-General Kofi Annan. It expressed profound concern over the Nato military intervention and called for an immediate moratorium.

The Greek Orthodox condemned the action against "a heroic and Christian people such as the Serbs".

BBC Religious Affairs correspondent Jane Little said such rhetoric reflects the depth of solidarity in the Orthodox world for the predominantly Orthodox Serbs, and highlights the complex religious and ethnic factors which make this conflict so explosive.

Our correspondent also says Kosovo is the spiritual heartland of Serbian nationalism - symbolised by the hundreds of ancient monasteries and churches dotted throughout the region.