World Bulletin/News Desk

Seven loud explosions shook Nigeria's northeastern city of Maiduguri on Friday, witnesses said, hours after President Goodluck Jonathan ended a trip there to try to galvanise support for his battle against Boko Haram.

Witnesses said the explosions happened within minutes of each other, suggesting the kind of coordinated strike that used to be the hallmark of Boko Haram, before a military campaign weakened them.

President Jonathan spent the night in Maiduguri during was his first trip to the troubled northeast since becoming president.

During it, he poured cold water on the idea of an amnesty for the fighters and urged the region's tribal elders to do more to help fight.

The blasts in the Jajeri ward of the city occurred about five hours after he left in the afternoon, witnesses said.

There was no word on casualties and a security forces spokesman for the northeast was not immediately available for comment.

Traditional leaders accuse the security forces of being too heavy handed and indiscriminate, killing dozens of civilians.

"Instead of condemning the operations of the JTF (military and police joint task force) we should work to fight the insurgency," Jonathan said, replying to the criticism.

Jonathan said on Thursday he was not ready to offer an amnesty to members of Boko Haram, brushing aside a proposal from the country's most senior Muslim spiritual leader, the Sultan of Sokoto.

The sect's self-proclaimed leader Abubakar Shekau last week rejected the whole notion of peace talks in a video.

Boko Haram’s core group, believed to be led by Shekau, still focuses its attacks in its northeast base but the group is split into different factions spread across the north of Africa's most populous nation.

Criminal gangs have also sprung up, taking advantage of worsening security in the region.