KANO, Nigeria: Nigerian police foiled fresh attacks in the northern city of Kano Monday, discovering 10 bomb-laden cars and hundreds of other unexploded devices from a wave of deadly violence last week.
Clerics said prayers for peace after the attacks on Friday that killed at least 184 people in the country's second-largest city and stoked fresh fears of an all-out civil war in Africa's most populous nation and top oil producer.
President Goodluck Jonathan vowed to beef up security as he grapples with the worst crises of his nine-month tenure -- a surge in violence by the Islamist sect Boko Haram blamed for the attacks and mounting social discontent.
Kano, a mainly Muslim city of 4.2 million, was left reeling after bombs were set off and gun battles raged in coordinated strikes after Friday prayers that targeted mainly police buildings, including the police headquarters.
Details began to emerge Monday of the mode of the attacks, with police announcing the discovery of large numbers of explosive devices and that at five of the assailants were suicide bombers.
At least two dozen of the dead were police officers, police commissioner Ibrahim Idris said in a statement, while witness testimony said some of the assailants wore police uniforms.
He said police found 10 cars loaded with improvised explosive devices (IEDs) at various sites in Kano, along with about 300 drinks cans, eight powdered milk tins and eight 350-kilogramme drums -- all loaded with explosives.
According to the latest toll, he said 150 civilians, 29 policemen, three intelligence officers and two immigration officers had been killed.
Jonathan imposed emergency rule in parts of Nigeria's north on December 31 after a wave of violence blamed on Boko Haram. But Kano, which had escaped the worst of the violence in recent months, was not among the areas covered.
Jonathan said Sunday on a visit to Kano, an ancient Muslim holy city, that some suspects had been arrested and vowed that his government would strengthen security across the country and track down the sponsors of Boko Haram.
"I will pray to God that we should never re-live the catastrophe that resulted in the deaths and maiming in our city," Kano State governor Rabiu Musa Kwankwaso said as about 200 Muslim clerics and political leaders offered peace prayers in Kano.
Nobel literature laureate Wole Soyinka, who has previously warned of the risk of civil war, appealed to fellow Nigerians not to exact revenge.
"We must not accept the agenda of Boko Haram. Do not consider reprisals," Soyinka said. "They want... to embark on a programme where neighbours will turn against neighbours."
Political leaders also sought to ensure that the attacks did not spark a wider conflict in Nigeria, which is roughly divided between a mainly Muslim north and predominantly Christian south.
"We want to ensure that a few misguided Nigerians who have been led into this action don't take this country hostage," said Senate president David Mark who travelled to Kano with the speaker of the House of Representatives Aminu Tambuwal.
"Even though it is a big challenge... it is not one that... shakes Nigeria to its foundation," former president Olusegun Obasanjo said on Sunday.
A purported spokesman for Boko Haram said the attacks were in response to a refusal by the authorities to release its members from custody.
Some detainees being held at a police station in Kano were thought to have been freed during Friday's attacks.
The group, which has staged a series of increasingly sophisticated and bloody attacks, often targeting Christians, is believed to have a number of factions with differing aims, including some with political links and a hard-core Islamist cell.
Jonathan has said some Boko Haram members have infiltrated government, including the security services and the executive.
In Kano, around 50 people gathered Monday outside the main hospital's morgue waiting to collect remains of their loved ones for burial.
Assistant Police Superintendent Wellington Asiayei said from his hospital bed that he was shot in the spinal cord by a man in police uniform at the police barracks.
"I thought it was my colleague, so I said, 'Come sir, let's run to the headquarters. Something is happening.' So I was about to lock my door... I saw him raise the rifle at me."
Most of the recent major attacks blamed on the sect have occurred in the northeast of the country, with many taking place despite the state of emergency.
Boko Haram claimed a Christmas Day bombing at a church near the capital Abuja which killed at least 44 people and an August attack against UN headquarters in Abuja that killed 25.