AMMAN/VATICAN CITY • Christians in Aleppo celebrated under a giant Christmas tree lit up for the first time in five years after the city came back under full government control, as Christian leaders called for an end to violence in the Middle East.

The fall of rebel-held east Aleppo last week was the biggest victory of Syria's nearly six-year-old civil war for supporters of President Bashar al-Assad, and many in pro-government parts of the city were jubilant.

However, the rebel defeat has brought severe hardship on civilians who fled from insurgent-held areas, thousands of whom have been forced to camp in the wilderness under snow. Aid groups say many are in peril and children have died from exposure to the severe winter weather.

In the war-ravaged St Elias Cathedral located on what was long the front line in Aleppo's historic Old City, priests prayed for peace at the first Christmas Eve Mass for five years, attended by dozens of worshippers, including some Russian officers.

"The festive atmosphere is great. It's a new birth for Jesus Christ and a new birth for the city of Aleppo," said Mr George Bakhash, a Christian community leader. He added that the numbers attending mass across the city had surged, now that worshippers no longer feared missiles from rebel-held areas.

Many Syrian Christians supported the government in the civil war, viewing Mr Assad, a member of a Shi'ite-derived minority sect, as a protector against rebel fighters mainly drawn from Syria's Sunni Muslim majority.

In the comparatively undamaged parts of the city that had long been held by the government, restaurants were thronged by Christian patrons late into the night.

Hundreds of people danced and celebrated in the Azizya neighbourhood, where the public Christmas tree had gone unlit since rebels took the eastern half of the city in 2012.

Christian leaders from the Vatican to Bethlehem struck a sombre note in their Christmas messages, speaking of war, fear and division, as cities in Europe ramped up security in the shadow of last Monday's Berlin Christmas market attack that left 12 dead.

Addressing some 40,000 people gathered in St Peter's Square on Sunday, Pope Francis called for guns to fall silent in Syria, saying "far too much blood has been spilled" in the nearly six-year conflict, which has contributed to mass migration and homelessness.

In Bethlehem, some 2,500 worshippers packed the Church of the Nativity complex, built over the grotto where Christians believe Jesus was born, for midnight mass in the Israeli-occupied West Bank near Jerusalem.

Like Pope Francis, Archbishop Pierbattista Pizzaballa also used his homily to plead for compassion for refugees and for a halt to the violence in the Middle East.

Religious ceremonies in Germany were heavy with the weight of the Berlin attack, which was claimed by the Islamic State in Iraq and Syria.

"Christmas this year carries a deep wound - we are celebrating this festival in a different way this year," said Bishop Gebhard Fuerst of Rothenburg in the south-east.

In France, where the killings in Germany evoked memories of a terrorist truck rampage in June that left 86 people dead in Nice, 91,000 members of the security forces have been deployed to guard public spaces, including churches and markets over the weekend.

Meanwhile, for the first time in decades, Britain's 90-year-old Queen Elizabeth missed a traditional Christmas church service on Sunday owing to a heavy cold, a Buckingham Palace spokesman said.

REUTERS, AGENCE FRANCE-PRESSE