Christian groups protested Monday after a string of bombings attributed to the Islamic sect Boko Haram left at least 35 people dead Christmas Day.
Reuben Abati, a spokesman for the Nigerian government, said the country was on alert.
"We are dealing with anarchists who seem to be just as determined as the government, and that was on display yesterday," he was quoted by The Wall Street Journal as saying. "We will remain proactive."
Boko Haram claimed responsibility for an attack in early November that left at least 65 people dead in the northern Nigerian city of Damaturu. The group was blamed for the October deaths of a Nigerian lawmaker and a journalist as well as for an August attack on U.N. offices in Abuja.
Critics of Jonathan, a Christian, said the government wasn't taking the Boko Haram threat seriously.
Jonathan, however, described the attack as a "dastardly act" act that should "attract the rebuke of all peace-loving Nigerians."
Washington in early December published a 29-page report highlighting the perceived national security threat from Boko Haram.
Notable deaths of 2014 [PHOTOS]