31 December 2011 Last updated at 16:14 GMT
President Goodluck Jonathan offered his condolences to relatives of those killed on Christmas DayNigerian President Goodluck Jonathan has declared a state of emergency in areas worst affected by attacks from the Islamist group Boko Haram.
Borders would be closed temporarily in the north-eastern states of Yobe and Borno, and central state of Plateau.
Mr Jonathan vowed to “crush” Boko Haram, which killed dozens in attacks across the country on Christmas Day.
Speaking at a church in the capital, Abuja, where 37 people died, he described Boko Haram as “cancerous”.
His remarks follow urgent meetings held with security services.
Boko Haram is thought to be responsible for a string of major attacks across Nigeria this year.
It bombed the headquarters of the UN in August 2011, leaving at least 21 dead and has targeted police as well.
The attacks on Christmas Day left at least 42 dead. Tens of thousands of people have fled their homes in Maiduguri and other cities which have been attacked by Boko Haram, especially in Yobe state.
The president said Boko Haram “started as a harmless group… They have now grown cancerous”.
“And Nigeria, being the body, they want to kill it. But nobody will allow them to do that,” he said.
While offering his condolences to victims’ relatives at St Theresa’s Church in Abuja the president is quoted by Reuters news agency as saying: “We will crush the terrorists. If there are institutions… which are harbouring terrorists, we will deal with them,”
Boko Haram wants to impose strict Sharia law across Nigeria.
Earlier this week, Nigeria’s main Christian group warned that the community might have to defend itself if the security forces could not protect it.
Analysts said the move raised the spectre of communal clashes in Africa’s most populous nation, which is divided between a largely Muslim north and a mainly Christian and animist south.