Pope Francis has invited leaders of all Christian denominations in the Middle East to join him in Italy in July to discuss how they can help bring peace to the region, the Vatican says.
The meeting will take place on July 7 in the southern Adriatic port city of Bari, chosen because it is home to the relics of St Nicholas, a figure venerated in both the Western and Eastern branches of Christianity.
Nicholas, who lived about 1700 years ago in what is today Turkey, is particularly honoured by Christian Orthodox Churches in countries such as Syria, Iraq, Egypt and Lebanon in the Middle East.
Nicholas is also widely venerated among Orthodox Christians in Russia, which is Syria's ally in the civil war.
The Vatican said on Wednesday the encounter would be an "ecumenical meeting for peace" where the religious leaders would discuss "the dramatic situation of the Middle East that afflicts so many brothers and sisters in the faith".
Meanwhile the foreign ministers of Russia, Turkey and Iran will meet on April 28 to discuss Syria in Moscow, Interfax news agency says, citing a source at Russia's foreign ministry.
Separately the Russian military indicated on Wednesday it will supply the Syrian government with a sophisticated air defence system following Moscow's condemnation of the missile attack launched by the United States, Britain and France earlier this month.
Colonel General Sergei Rudskoi said Russia will supply Syria with "new missile defence systems soon."
Rudskoi's statement did not specify the type of weapons, but his remarks follow reports in the Russian media that Moscow is considering selling its S-300 surface-to-air missile systems to Syria.
Top Russian officials said that in light of the air strikes on Syria earlier this month, Moscow may reconsider a pledge it gave a decade ago not to provide Syria with the S-300 system.
The strikes were in retaliation to an April 7 suspected chemical weapons attack in the town of Douma, near Damascus, that killed more than 40 people.