Gunmen suspected to be Boko Haram Islamists have launched a fresh attack on a northeast Nigerian village killing two residents, two weeks after they beheaded 23 people in the same village, witnesses said.

The insurgents stormed Buratai village on motorbikes around 8:00pm (1900 GMT) on Thursday, killed their targets and fled, a security source said.

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.

Suspected Boko Haram gunmen opened fire on villagers and torched a number of buildings in a new attack in northeast Nigeria, witnesses said Monday.

Resident Ahmad Ali told AFP that roughly two dozen assailants, who were "obviously Boko Haram fighters" stormed the village of Kwajaffa at dusk on Sunday and ordered residents out of their homes.

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.

Two Al-Jazeera television journalists who had been detained by the Nigerian military since March 24 have been freed, the Qatar-based broadcaster said in a statement on Sunday.

It said Ahmed Idris and Ali Mustafa had been allowed to leave the Maiduguri hotel where they were detained, and return to the network's Abuja office.

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.

The black letters crudely painted on a wall at the entrance to the devastated town of Malam Fatori, in northeast Nigeria, spell out "God is great" -- a calling card from the evicted Boko Haram fighters.

Niger and Chadian army troops, working together in support of Nigerian forces, recaptured the town on Tuesday to find grocery stores vandalised, smoke-blackened walls and motorbikes and wheelbarrows lying abandoned on the ground.

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.

Gunmen stormed two communities in Nigeria's southern oil state of Rivers, killing at least nine people and injuring two others a week ahead of a gubernatorial election, police said Saturday.

"It was about 19:30 hours (1830 GMT) of yesterday (Friday). Some unknown armed men invaded Obrikom and Obor communities and went on a shooting spree," state police spokesman Ahmad Muhammad said in a statement.

The Pope led Catholics in prayer for persecuted Christians around the world at a Good Friday service in Rome, a day after 148 students and security officers were massacred by Shebab Islamists in Kenya.

A small group of believers carried a cross between 14 "stations" evoking the last hours of Jesus's life during the traditional Via Crucis (Way of the Cross) procession, as the Pope looked on.