MAIDUGURI, Nigeria — Four suicide bomb attacks Saturday hit the city of Maiduguri killing at least 54 people and wounding 143 in the heartland of Nigeria's northeastern Islamic uprising, police said.
The blasts occurred over four hours in locations from a busy fish market to a crowded bus station, said Police Commissioner Clement Adoda.
A fifth explosion from a car bomb at a military checkpoint 75 kilometers (50 miles) outside the city wounded a soldier and two members of a civilian self-defense unit. The bomber apparently wanted to reach Maiduguri, said a police officer at the scene who spoke on condition of anonymity because he is not allowed to speak to the press.
In the deadliest blast, 18 people died when a suicide bomber blew himself up in a tricycle taxi at the entrance to the bustling Baga fish market, police said.
"I saw many dead bodies lying on the ground, many dead, and several others badly injured," said fish seller Idi Idrisa.
About an hour later a second explosion rocked the Post Office shopping area near the market, according to witness Baban Musa, who said there were many casualties.
A third blast was detonated at Monday Market, the biggest in Maiduguri, and a fourth explosion ripped through the Borno Express bus station.
No one immediately claimed responsibility for the attacks but they bear the hallmarks of the Boko Haram Islamic extremist group. Maiduguri is the birthplace of Boko Haram and the extremists have tried to seize the city with armed assaults by hundreds of fighters and have made it the target for many bombings since they were driven from their base there after a military state of emergency was declared in May 2013.
Boko Haram has increased suicide bombings and village attacks in recent weeks as forces from Nigeria and Chad have driven the insurgents from a score of towns along Nigeria's border with Cameroon.
The insurgents also have attacked villages in Cameroon and Niger in response to Nigeria's neighbors forming a multinational force to confront the spreading Islamic uprising.
Chad's President Idris Deby this week said his forces know the whereabouts of Boko Haram leader Abubakar Shekau and warned him to surrender or face death.
Boko Haram fighters are massing at their headquarters in the northeastern town of Gwoza, in apparent preparation for a showdown with multinational forces, according to witnesses who escaped from the town.
An intelligence officer said they were aware of the movement but that the military is acting cautiously as many civilians still are trapped in the town and Boko Haram is laying land mines around it.
Maiduguri is the capital of Borno state and the biggest city in northeastern Nigeria, the heart of an Islamic uprising that has killed about 12,000 people in nearly six years.