VATICAN CITY - Pope Benedict XVI prayed for the victims of famine, floods and conflict in his Christmas message Sunday as a string of bomb attacks targeting churches in Nigeria killed dozens.
The 84-year-old pontiff notably called for an end to the bloodshed in Syria and said he hoped this year's Arab revolts would aid the "common good."
"May the Lord come to the aid of our world torn by so many conflicts which even today stain the earth with blood... May he bring an end to the violence in Syria, where so much blood has already been shed," the pope said.
His strongest words were against war and in favour of reconciliation, particularly between Israelis and Palestinians in the Holy Land but also in the Great Lakes region of Africa and the new nation of South Sudan.
"May he grant renewed vigour to all elements of society in the countries of North Africa and the Middle East as they strive to advance the common good," he told thousands of pilgrims at the Vatican in a year that saw the overthrow of dictators in Egypt, Libya and Tunisia.
In religiously-divided Nigeria, Africa's most populous nation, at least 40 people were killed when five separate bomb attacks claimed by Islamist sect Boko Haram targeted churches during Christmas services.
A purported Boko Haram spokesman claimed responsibility for all of Sunday's attacks, which also included a suicide bombing outside the offices of secret police in the northeastern city of Damaturu.
The spokesman, Abul Qaqa, also told AFP the group would launch more attacks "in the next few days."
The United States condemned the violence, with the White House saying it had spoken with Nigerian officials "about what initially appear to be terrorist attacks" and had pledged to help bring the perpetrators to justice.
European leaders also expressed revulsion at the attacks, with German Foreign Minister Guido Westerwelle lamenting that "even on Christmas Day, the world is not spared from cowardice and the fear of terrorism."
Benedict urged the international community to aid those suffering from hunger in the Horn of Africa and prayed for the victims of recent flooding in Thailand and the Philippines, which he said were enduring "grave hardships."
Thousands of flood survivors queued for Christmas meals in evacuation centres in the Philippines, where a devastating storm last week left more than 2,000 dead or missing and some 328,000 others relying on emergency aid.
Australians endured intense Christmas weather, with a tropical cyclone closing in on the north as tornadoes and thunderstorms brought hail in the south and huge swells forced holiday revellers off popular beaches.
Britain's royal family marked a subdued Christmas, with Princes William and Harry visiting their grandfather Prince Philip, the queen's 90-year-old husband, in the hospital where he was recovering from heart surgery.
In her annual pre-recorded Christmas address, Queen Elizabeth II said that in times of hardship we often "find strength from our families."
US President Barack Obama and his family went to church on a military base in Hawaii to celebrate the holiday.
Obama, his wife Michelle and daughters Malia, 13, and Sasha, 10, went to the chapel at Kaneohe Marine base after singing carols and opening their presents at the vacation residence they are renting.
The White House said Obama also made telephone calls on Christmas Eve to 10 service members from the Marines, Air Force, Navy and Army who are serving overseas.
In a Christmas message, the president and his wife this week thanked all US troops and their families for their service to the United States.
"Our troops are coming home. And across America, military families are being reunited," Obama said in his weekly radio and Internet address.
"Let's say a prayer for all our troops standing post all over the world, especially our brave men and women in Afghanistan who are serving, even as we speak, in harm's way to protect the freedoms and security we hold dear."
With the run-up to Christmas marked by a global shopping frenzy that has only grown in intensity in recent years, the pope lamented the consumerism surrounding the holiday.
"Let us ask the Lord to help us see through the superficial glitter of this season, and to discover behind it the child in the stable in Bethlehem, so as to find true joy and true light," he said during Christmas Eve mass in Saint Peter's Basilica.
Peace was also a central theme in Patriarch of Jerusalem Fuad Twal's Christmas Eve homily delivered in Bethlehem, where hotels and guesthouses were packed to capacity.
"We ask for peace, stability and security for the entire Middle East," said Twal, the most senior Roman Catholic in the region.
In a midnight mass, he urged "the return of calm and reconciliation in Syria, in Egypt, in Iraq and in North Africa."
Bethlehem, the biblical birthplace of Jesus, saw some of its largest crowds of tourists in years, bringing cheer to the Israeli-occupied West Bank, while celebrations also passed without incident in Iraq.