Nigeria’s president has pledged “to leave no stone unturned” in tracking down the perpetrators of a mosque attack that killed dozens of people.
Goodluck Jonathan urged the nation “to confront the common enemy” after the gun and bomb attack during Friday’s prayers in the northern city of Kano.
Many more people were injured, with one rescue official putting casualty figures at almost 400.
Officials said the attack bore all the hallmarks of Boko Haram militant group.
However, no-one has so far claimed responsibility for Friday’s assault.
Separately, the security forces said they had foiled an attempt to attack worshippers in the north-eastern city of Maiduguri, defusing six bombs planted in a mosque and a nearby market.
Boko Haram has been waging an insurgency in Nigeria since 2009 – and has killed more than 2,000 people this year, rights groups say.
In a statement, President Jonathan ordered the country’s security services “to launch a full-scale investigation and to leave no stone unturned until all agents of terror undermining the right of every citizen to life and dignity are tracked down and brought to justice”.
He said Nigerian should “remain united to confront the common enemy”.
He said the government would “continue to take every step to put an end to the reprehensible acts of all groups and persons involved in acts of terrorism”.
Police said 35 people were killed in the attack at the Central Mosque, but some eyewitnesses claimed that far more people lost their lives.
The rescue official, speaking to Agence France-Presse, put the casualty toll at 120 dead and 270 hurt, although this has not been independently confirmed.
Three bomb explosions were reported in and around the mosque. The attackers also turned gunfire on worshippers.
Some reports say the first bomb was hidden in a car which was driven straight into the worshippers.
One eyewitness told the BBC’s Focus on Africa: “The imam was about to start prayer when he saw somebody in a car trying to force himself into the mosque. But when people stopped him, he detonated the explosions. People started running helter-skelter.”
But then several men then opened fire on the crowd, killing more people. Three of the gunmen were caught, and – as the terror turned to rage – they were killed on the spot, the BBC’s Will Ross in Abuja reports.
BBC Hausa editor Mansur Liman said one witness at a local hospital had described the scenes there as being the most horrible he had ever seen.
The Central Mosque is where the influential Muslim leader, the Emir of Kano, usually leads prayers.
The emir recently called for people to arm themselves against Boko Haram.
Boko Haram has stepped up attacks against civilian targets since the Nigerian military launched an offensive last year.
The militants were also behind the kidnapping of more than 200 schoolgirls from Chibok in Borno state this year, an act that sparked international outrage.