"We condemn this senseless violence and tragic loss of life on Christmas Day," the White House said in a statement. "We offer our sincere condolences to the Nigerian people and especially those who lost family and loved ones."
The coordinated church bombings -- including an explosion in front of a church in Madala, a suburb of the capital, Abuja, that ripped through a crowd of worshipers as they left morning mass -- left bodies charred and cars and trucks mangles.
A radical Muslim sect known as Boko Haram claimed responsibility.
At least two other churches in other towns were also attacked, as was a police headquarters in a northern area where dozens have been killed in a bloody conflict in recent days between the security forces and the sect.
Officials said the attack on the police headquarters was a suicide bombing and that killed at least three officers.
Crowds at St. Theresa Catholic Church in Madala were angered by the attack and the slow response of emergency services, the BBC reported.
French President Nicolas Sarkozy expressed "solidarity in (Nigeria's) fight against terrorism," while German Foreign Minister Guido Westerwelle said, "Even on Christmas Day, the world is not spared from cowardice and the fear of terrorism."
British Foreign Secretary William Hague called the attacks "cowardly" and Israel, after condemning "in the strongest terms these attacks carried out on Christmas Day," said it would send medical aid to Nigeria.
The Boko Haram sect -- also known as People Committed to the Propagation of the Prophet's Teachings and Jihad -- seeks the strict implementation of its interpretation of Sharia across the country.
Boko Haram, which roughly translates as "Western education is sacrilege," has waged an insurgency against the government since 2009, mostly through bombings.
It opposes not only Western education, but Western culture and modern science as well. In its view, Nigeria is run by non-believers.
The group -- which also claimed responsibility for a string of Christmas Eve 2010 bomb blasts in the central Nigeria city of Jos, dubbed "Jesus Our Savior" by residents -- is responsible for more than 450 killings in Nigeria this year.
Nigerian President Goodluck Jonathan, who is Christian, said Sunday's attacks were "an unwarranted affront on our collective safety and freedom."
"Nigerians must stand as one to condemn them," he said, adding Nigeria's government would "not relent in its determination to bring to justice all the perpetrators."