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.
The president said he was committed to fighting terrorism despite criticism that he has failed to ensure security.
‘Enemies of human progress’
Nigeria is facing a sustained campaign by the Islamist Boko Haram militant group who last month abducted 200 girls from a boarding school in the north-eastern town of Chibok.
President Jonathan described Tuesday’s 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,” his office said.
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.
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 limbs blown off – besides fires still raging out of control eight hours after the attack.
Dozens of those dead and injured 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,” National Emergency Management Agency (Nema) Zonal Co-ordinator Mohammed Abdulsalam told the Associated Press.
He said the fires were being fuelled by flammable goods at the market, including rubber sandals.
A spokesperson for the regional governor 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.
Analysis by Will Ross, BBC News, Abuja
Once again the explosions were meant to cause as many casualties as possible. Like the recent Abuja blasts, the victims are of different religions and were mainly people out on the streets struggling to earn a living.
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.
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.
Meanwhile critics have questioned the military’s tendency to use conventional tactics to fight an enemy waging a guerrilla war – they argue that “soft power” strategies could also be used.
More than 2,000 people, most of them civilians, have been killed this year, according to Nema, human rights and monitoring groups.
Diplomats on Tuesday said that Nigeria has asked a UN Security Council committee responsible for imposing sanctions against al-Qaeda-linked groups to nominate Boko Haram as a terrorist organisation.
Sporadic militant attacks in Cameroon, Chad and Niger have heightened fears of a regional war.
On Saturday President Jonathan and his counterparts from neighbouring countries agreed to boost co-operation to tackle the problem.
