The Pope urged loyal Catholics in China to have courage in the face of communist limits on religious freedom and conscience.
In Bethlehem, the largest number of pilgrims in a decade gathered to celebrate Christmas, with tens of thousands flocking to the Church of the Nativity for prayers. Bombings in Nigeria and the Philippines left 11 dead and 11 injured, however, and fear in Iraq also marred the Christmas festivities.
Benedict used his traditional holiday speech, delivered from the central balcony of St. Peter's Basilica to tourists and pilgrims in the rain-soaked square, to encourage people living in the world's troublespots to take hope from the "comforting message" of Christmas. Those areas range from strife-torn Afghanistan to the volatile Korean peninsula to the Holy Land where Jesus was born -- and even to China.
In recent weeks, tensions have flared anew between the Vatican and Beijing over the Chinese government's defiance of the pope's authority to name bishops and its insistence that prelates loyal to Rome attend a gathering against their will to promote China's state-backed church.
"May the birth of the savior strengthen the spirit of faith, patience and courage of the faithful of the church in mainland China, that they may not lose heart through the limitations imposed on their freedom of religion and conscience but, persevering in fidelity to Christ and his church, may keep alive the flame of hope," Benedict prayed aloud.
Chinese church officials did not immediately comment late Saturday. On Friday, one said the Vatican bears responsibility for restoring dialogue after it criticized leadership changes in China's government-backed church.
The pope also expressed hope that Christmas might inspire respect for human rights in Afghanistan and Pakistan and "advance reconciliation on the Korean peninsula."
For Africa, Benedict spoke hopefully that "horizons of lasting peace and authentic progress" would open up for the peoples in Somalia and Darfur as well as those in the Ivory Coast, where Laurent Gbagbo has been resisting warnings from West African leaders to step down peacefully or risk being removed by force after a presidential election the international community insists he lost.
Persecution of Christians in the world has been an increasingly pressing concern of the Vatican of late, with the pope earlier this month denouncing the lack of freedom of worship as an intolerable threat to world security.
Benedict has repeatedly spoken out about the plight of Christians in Iraq, many of whom have fled their country to escape persecution and violence, including after an attack on a Baghdad basilica. He prayed that Christmas would "ease the pain and bring consolation amid their trials to the beloved Christian communities in Iraq and in the Middle East."
"May the light of Christmas shine forth anew in the land where Jesus was born, and inspire Israelis and Palestinians to strive for a just and peaceful coexistence," Benedict said in his traditional "Urbi et Orbi" address (Latin for 'to the city and to the world').
In Bethlehem, it was the busiest Christmas in years.
Over 100,000 pilgrims poured into the West Bank town since Christmas Eve, twice as many as last year, Israeli military officials said, calling that the highest number of holiday visitors in a decade. They spoke on condition of anonymity because they were not authorized to talk to the media.
In Nigeria, at least 11 people were killed in multiple Christmas Eve blasts in the country's central region, where tensions often boil over between Christians and Muslims.
Gregory Yenlong, the Plateau State information commissioner, told The Associated Press that he counted 11 dead bodies at two sites rocked by bombs in Jos, a city long plagued by religious violence. He said no one has claimed responsibility for the attacks.
Another bomb exploded during Christmas Day Mass at a police chapel in the volatile southern Philippines, wounding a priest and 10 churchgoers. The improvised explosive was hidden in the ceiling of the police camp chapel in Jolo on Jolo Island, a stronghold of al-Qaida-linked militants.
Christians also marked a somber Christmas in Baghdad in the face of repeated violence by militants intent on driving them out of Iraq.
Hundreds gathered at a Baghdad church where Muslim extremists in October took more than 120 people hostage in a standoff that ended with 68 dead. Church walls were pockmarked with bullet holes, plastic sheeting hung instead of glass windows and flecks of dried flesh and blood still speckled the ceiling.
After the siege, about 1,000 Christian families fled to the relative safety of northern Iraq, according to U.N. estimates.
"No matter how hard the storms blows, love will save us," Archbishop Matti Shaba Matouka told those gathered, urging Iraqi Christians not to flee the country.
In Bethlehem, pilgrims and tourists posed for pictures and enjoyed the sunshine Saturday while others thronged the Church of the Nativity to attend Mass. Worshippers also packed the Roman Catholic church next to the grotto where the traditional site of Jesus' birth is enshrined.
The town's 2,750 hotel rooms were booked solid for Christmas week. Only one-third of Bethlehem's 50,000 residents are Christian today, down from 75 percent in the 1950s. The rest are Muslims. Overall, Christians only make up 2 percent of the population in the Holy Land today, compared to 15 percent in 1950.
"(It's) a really inspiring thing to be in the birthplace of Jesus at Christmas," said Greg Reihardt, 49, from Loveland, Colorado.
Still, visitors entering Bethlehem had to cross through a massive metal gate in the separation barrier that Israel built between Jerusalem and the town during a wave of Palestinian attacks in last decade.
In eastern England, members of Britain's royal family attended the traditional Christmas morning service at their Sandringham estate.
Queen Elizabeth II appeared at St. Mary Magdalene Church bundled in a winter coat and large furry hat. Hundreds of onlookers watched as other family members arrived, including Prince Harry, Prince Charles and his wife Camilla.
Prince William and his fiancee Kate Middleton were not there because William is on Royal Air Force duty in Wales. Middleton is believed to be spending Christmas Day at her family's home in Bucklebury, west of London.
Later, the queen's annual Christmas Day message will be broadcast, which this year focuses on how sports can be used to build communities.
At airports in Paris and Brussels, hundreds of travelers received their own special Christmas present -- a flight out after spending Christmas Eve curled up on hard terminal floors.
"I've never had such a Christmas before," said Ron Van Kooe, who slept at the Brussels terminal. "It's one not to forget."
The Associated Press contributed to this report.