Abuja- Nigerian President Goodluck Jonathan has condemned twin bombings in the central city of Jos, in which at least 118 people were killed.
Mr Jonathan said those who carried out the attack were “cruel and evil”.
It is feared more bodies still lie under the rubble of buildings destroyed by the explosions, which targeted a crowded market and a hospital on Tuesday.
Nigeria has been facing a sustained campaign by the Islamist Boko Haram militant group. Last month, Boko Haram abducted 200 girls from a boarding school in the north-eastern town of Chibok.
The president said he was committed to fighting terrorism despite criticism that he has failed to ensure security.
His office described the attack as a “tragic assault on human freedom”.
“President Jonathan assures all Nigerians that [the] government remains fully committed to winning the war against terror and... will not be cowed by the atrocities of enemies of human progress and civilisation,” it said in a statement.
He announced increased measures to tackle the militants, including a multinational force around Lake Chad, which comprises a battalion each from Chad, Niger, Cameroon and Nigeria.
If this is once again the work of Boko Haram, it shows the Islamist extremist group’s determination to expand its area of operation and prove that it can strike where it wishes, analysts say.
The second blast in Jos came 30 minutes after the first, killing rescue workers who had rushed to the scene, which was enveloped by clouds of black smoke.
“It’s horrifying, terrible,” said Mark Lipdo of the Stefanos Foundation, a Christian charity-based in the city, who said the air was heavy with the smell of burning bodies.
Witnesses described a grim scene of dead and badly injured people - some with their limbs blown off - as fires were still raging out of control eight hours after the attack.
Dozens of casualties were covered in grain that had been loaded in the second car bomb, witnesses said.
“Firemen are still trying to put several blazes out. We believe we will find more bodies,” a spokesperson for the National Emergency Management Agency said.
He said the fires were being fuelled by flammable goods at the market, including rubber sandals.
The regional governor’s office told AFP news agency that most of the victims were women.
The market and bus terminal are part of the commercial centre of Jos.
Correspondents say that Nigeria is under renewed worldwide attention over its response to Boko Haram, especially given the global attention on the plight of the missing school girls.
Churches targeted: It has been almost two years since the last attack on Jos - when several churches were bombed. Those attacks were seen as an effort by Boko Haram to spark clashes between Christians and Muslims in the often volatile Middle Belt region of Nigeria.
Religious clashes: For more than 10 years this area has been the scene of violent clashes that have often been portrayed as religious conflicts even though they are rooted in competition over land, power and resources.
There is, however, a risk that these latest bombings will spark reprisal clashes and religious leaders have appealed for calm.