Seventy-one Chadian soldiers have been killed and 416 injured in two-and-a-half months' fighting Boko Haram, the Chadian army said on Friday.

Chad is taking part in a regional offensive against the Nigeria-based Islamist radicals along with troops from Nigeria, Niger and Cameroon.

Seven civilians were killed in an attack in Chad blamed on Nigerian Boko Haram rebels, officials said Monday.

The Islamist militants ambushed people on their way to a market in Tchoukou Telia near Lake Chad on Friday, Dimouya Souapebe, the deputy prefect of Baga Sola told Agence France Presse.

Central and west African leaders will hold a summit next week to fine tune their campaign to crush Boko Haram, who appear to be losing ground in the face of a regional military offensive.

The April 8 talks will be the first since Nigeria's election a week ago which was won by Muhammadu Buhari, a former military leader who has vowed to rid his country of the "terror" the Islamist militants have sown.

At least four people were killed Saturday when suspected Boko Haram fighters raided a local market in a village near the northeast Nigerian city of Maiduguri, security sources said.

Scores of Boko Haram gunmen stormed Kayamla village, 20 kilometers (12.5 miles) from Maiduguri, capital of restive Borno state, and opened fire on a weekly market, killing four traders, a senior security official in Maiduguri told Agence France Presse.

Nine Chadian soldiers were killed and 16 wounded after being ambushed by Boko Haram fighters in northeastern Nigeria, the Chadian army said Thursday.

A military spokesman said fighting took place on Wednesday about 10 kilometers (six miles) from the town of Malam Fatori, which Niger said was retaken by regional forces fighting the Islamist radicals earlier this week.

Troops from Niger and Chad killed 47 Boko Haram fighters when they repelled an attack by the Islamist insurgents in southeastern Niger, Chad's army said on Tuesday. 

The fighting took place in Bosso, a Niger village near the border with Nigeria.

Chad's President Idriss Deby has accused Nigeria of downplaying the threat from Boko Haram and failing to cooperate with the regional coalition battling the jihadists, saying there had been zero contact between their armies.

"The whole world is asking why the Nigerian army, which is a big army... is not in a position to stand up to untrained kids armed with Kalashnikovs," Deby told French magazine Le Point, in an interview published this week.

The United Nations Human Rights Council will hold a special session next week on abuses by Boko Haram militants in Nigeria and neighboring countries, the council president said Friday.

The rights council rarely convenes special sessions, with only 22 held since the body was created in 2006.

More than 1,000 civilians have been killed in Boko Haram attacks in the first three months of this year, Human Rights Watch said on Thursday.

"Each week that passes we learn of more brutal Boko Haram abuses against civilians," the group's Nigeria researcher, Mausi Segun, said in an emailed statement.

Seven of former Chadian leader Hissene Habre's security chiefs were jailed for life Wednesday for torture and murder by a special court in the capital N'Djamena.

They included the ex-head of the political police Saleh Younous and Mahamat Djibrine, who investigators said was one of the "most feared torturers" under Habre's eight-year dictatorship.