Boko Haram, the radical Sunni jihadists who want to create a hardline Islamic state in northeast Nigeria, has previously been blamed for attacks on Shia Muslims in the region
N'Djamena (AFP) - Around 100 bodies were found Friday in a mass grave on the edge of a town in northeast Nigeria after it was freed from Boko Haram Islamists, a Chadian army spokesman told AFP.
Soldiers discovered the bodies -- some decapitated -- under a bridge just outside Damasak, which was retaken from Boko Haram on March 9 by troops from Chad and Niger.
"There are about 100 bodies spread around under the bridge just outside the town," said Colonel Azem Bermandoa Agouna, adding that he had visited the scene himself close to the border with Niger.
He claimed the massacre probably occurred about two months ago and said: "This is the work of Boko Haram."
It was, however, impossible to verify the claim independently.
Colonel Bermandoa Agouna said several of the victims had been decapitated while others had been shot. "There are heads here and bodies there, the mass grave has become like a termite mound," he added.
Chad and Niger launched a vast air and ground offensive against Boko Haram in the area on March 8, quickly taking Damasak from the Nigerian Islamist militants.
According to a Chadian army source, the militants suffered heavy losses in the push, with some 200 killed in fighting on Sunday for the loss of 10 Chadian soldiers with 20 wounded.
- Rebels 'cleared' -
"Operation Mai Dounama", named after a 13th-century emperor of Borno province in northern Nigeria, aims to destroy Boko Haram bases close to Niger, a Nigerien army spokesman said Thursday.
Boko Haram took Damasak on November 24, killing around 50 people and forcing another 3,000 to flee, according to the UN's High Commissioner for Refugees.
The Islamist uprising, which initially began as a campaign against Western education, has claimed more than 13,000 lives since 2009.
The group recently allied themselves with the Islamic State group in Syria and Iraq.
The Nigerian military has been struggling for years to stamp out the movement and President Goodluck Jonathan, who is facing an election next weekend, has faced fierce criticism over his government's failure to contain the violence.
The presidential and parliamentary polls were initially due in February but were postponed by the election commission which cited security fears.
Nigeria has claimed major recent gains against the Islamists with the help of coalition partners Cameroon, Chad and Niger, achieving in just over one month what for years it had failed to do on its own.
Two out of three of the worst-hit northeast states -- Yobe and Adamawa -- have been declared "cleared" while the third, Borno, is expected to be liberated "soon", the military said this week.
Major towns such as Bama and Dikwa are among some 36 localities recaptured, with just three said to be still in rebel hands.