Kano - Nigerian forces raided the hideout of Islamist militants in Kano on Tuesday, killing the suspected mastermind of an attack on Christian worshippers, in a gun battle that lasted several hours in the main northern city.

The raid followed a spate of attacks in the past days, believed to be by the Islamist sect Boko Haram, which killed 30 people and dampened hopes that tighter security in the north had drastically reduced the sect's capability.

Residents of the Bubugaje slum area of Kano awoke to several loud explosions and the sound of gunfire.

“It is really terrifying... Everyone is indoors,” said Anthonia Okafor, a student at Kano university.

Hundreds have died in violence across the north and in the capital Abuja since the Islamists launched their uprising in 2009, targeting authorities, security forces and more recently the north's Christian minority.

“Our men just raided one of the hideouts of the elements... where we discovered explosives and weapons,” said Lieutenant Iweha Ikedichi, a spokesperson for the Joint Task Force (JTF) in Kano, Nigeria's second biggest city.

“The main suspect has been killed,” he added, referring to the suspected mastermind of an attack on a university in Kano on Sunday, when gunmen sprayed bullets in a lecture theatre being used for Christian worship.

That attack and another one on Sunday against a church in northeast Maiduguri, Boko Haram's spiritual headquarters, killed a total of 19 people.

Nigerian forces took journalists to the scene of the battle, a hot, dusty slum at the edge of a rusting industrial estate. They brought out three women and two children they said had been rescued from the house, which was partly demolished by fighting.

The front wall was blasted off and the iron roof had collapsed.

“The most difficult task we face with these terrorists is they know us but we don't know them. They're not rooted in a particular place,” Kano army commander Brigadier General Ilyasu Abba said, facing the house pocked with bullet and bomb craters.

“We have rooted them out of here today, but tomorrow they could be somewhere else,” he said, adding that one suspect was arrested but two had escaped through the back door.

One of them, university graduate Mohammed Ali Ibrahim, was later captured, Ikedichi said.

Police Commissioner for Kano State Ibrahim Idris told Radio Nigeria that AK-47 assault rifles, 467 munitions and 45 cans full of explosives were seized in the raid in Kano, an ancient Islamic city once at the heart of the merchant caravan routes stretching across the Sahara from Africa's interior to the Mediterranean.

Boko Haram says it is fighting to reinstate a 19th century Islamic caliphate in Africa's most populous nation, whose 160-million people are split roughly evenly between Muslims and Christians along north-south lines.

“We condemn attempts by those in Nigeria who seek to inflame Christian-Muslim tensions,” US Secretary of State Hillary Clinton said in a statement, referring to what she called Sunday's “disgraceful assault during church services”.

“We support those who recognise Nigeria's ethnic and religious diversity as one of the country's greatest strengths.”

Boko Haram's attacks have replaced militancy in the oil rich Niger Delta as the main security threat to the administration of President Goodluck Jonathan, a southern Christian, and it has gained momentum since his election victory a year ago.

A bomb blast struck a police chief's convoy in previously peaceful eastern Taraba state on Monday, killing 11 people.

Suicide car bombers targeted the offices of This Day newspaper in Abuja and in Kaduna last week, killing at least four people and demonstrating the sect's continued ability to carry out co-ordinated strikes. - Reuters