An explosion near a Coptic Christian church in Alexandria, Egypt, on Saturday killed at least 21 people and wounded 79.
The attack occurred after a New Year's Eve service. It was the deadliest terrorist attack in the north African country in recent years.
President Barack Obama released a statement on New Year's Day, strongly condemning the bombing.
"The perpetrators of this attack were clearly targeting Christian worshipers, and have no respect for human life and dignity," he said. "They must be brought to justice for this barbaric and heinous act."
Obama noted that they are continuing to gather information regarding the attack and ensured that the U.S. would offer the government of Egypt assistance, if necessary, to respond to the violence.
Also condemning the bombing, European Union High Representative Catherine Ashton said there cannot be any justification for the attack.
According to the country's interior ministry, the attack was likely carried out by a suicide bomber.
The government of Egypt responded by increasing security. Notably, the explosion took place even as security forces were posted outside the church during the New Year's Eve worship service.
Egyptian President Hosni Mubarak expressed alarm over the terrorism act and said it "hurts hearts of the Egyptians, Muslims and Coptics." He urged Copts and Muslims to together stand against terrorism.
Christians make up eight to 12 percent of the country's population. Though the constitution provides for freedom of belief and the practice of religious rites, respect for religious freedom by the government remains poor. The government has failed to prosecute perpetrators of violence against Coptic Christians in a number of cases.
The New Year's Eve attack occurred just a week after the state minister announced that the government is in talks with Coptic church leaders about easing its policy on the construction of churches.
Currently, it is virtually impossible for Christians to build new churches in Egypt and difficult to repair existing buildings. Construction of a new church requires a presidential permit and security clearance, while repairs demand permission from the local governor and security force.
There are about 2,000 churches in Egypt.