The Nigerian armed group Boko Haram has attacked two border towns inside the neighbouring country of Niger, marking the second foreign country attacked by the fighters in recent days.
Niger's defence minister said that the group attacked Bosso and Diffa early on Friday, before security forces fought back, killed 109 Boko Haram fighters, and forced them to retreat.
Four soldiers and a civilian were also killed in the fighting. Two other troops were missing and 17 members of the security forces wounded in the unrest, the minister added.
The region of Niger where the violence took place is an area where refugees already have arrived by the thousands seeking safety from Boko Haram attacks elsewhere.
The escalation in violence came as regional leaders meet for a second day in the Cameroonian capital to finalise plans for a coordinated military response to the group blamed for killing 10,000 people over the past year.
In the past two days, Boko Haram fighters have attacked Cameroonian border town of Fotokol, killing nearly 100 people and razing mosques and churches, according to Cameroonian officials.
"They (Boko Haram) attacked and burnt three mosques in the attack," Mele Mohammed, a Fotokol community leader, told the AFP news agency.
"In the mosque, in the Tashangalau area, they killed 31 people who were praying."
The Boko Haram attacks came after Chadian troops entered the Nigerian town of Gamboru close to Fotokol to flush out the armed men. The ensuing clashes left more than 200 Boko Haram fighters dead, according to Chadian military.
Prior to the ground offensive Chad's air force carried out strikes on the rebel positions in Cameroon.
Last week, African leaders authorised a 7,500-strong force to fight the rebels, including pledges of troops from Nigeria, Cameroon, Chad, Niger and Benin.