Soldiers are seen at the scene of a suicide bombing at a bus station in Kano, February 24, 2015.[Photo/Agencies]

"TIDE HAS TURNED"

"President Goodluck Jonathan condemns the reversion by the terrorist group Boko Haram to the callous bombing of soft targets ... in the wake of the rapid recovery by Nigerian troops and their multinational allies of areas formerly controlled by the sect," his office said in a statement.

"The days of mourning victims of incessant terrorist attacks in the country will soon be over as the tide has now definitely turned against Boko Haram."

A mine planted by Boko Haram killed at least two soldiers on Tuesday in the town of Bosso in Niger's southeastern region of Diffa, Niger's defence ministry said.

Last Saturday, Nigerian troops backed by air strikes seized the northeastern border town of Baga from Boko Haram, the military said, a significant victory in the offensive.

And on Tuesday, Chad claimed its soldiers had killed 207 Boko Haram militants and seized large stocks of weapons and ammunition in fighting near the Nigerian town of Garambu, close to the border with Cameroon.

But failure to protect civilians is a major criticism of President Goodluck Jonathan's administration ahead of an election scheduled for March 28.

Yobe state and Kano have both seen many Boko Haram attacks but have never been taken over by the militants the way northeastern Borno state has and are hundreds of miles from the main theatre of the war against the insurgents.

On Monday, defence spokesman Major-General Chris Olukolade said air strikes were under way on Boko Haram targets in the Borno state towns of Gwoza, where the group first declared an Islamic state, and Bama and Sambisa.