Satellite images and witnesses are challenging the Nigerian government's denials of mass casualties and damage which followed fighting between the military and Islamists in mid-April.
The rights group Human Rights Watch (HRW) has released satellite images showing massive destruction in Baga, a town in northeast Nigeria.
Clashes between soldiers and Boko Haram Islamists in the town on 16 and 17 April sparked massive fires that left nearly half of it destroyed.
HRW said it had analyzed satellite images and identified "2,275 destroyed buildings, the vast majority likely residences, with another 125 severely damaged."
On its website, it posted images depicting aerial shots of the town on April 6 against those of the same neighborhoods on April 26, 10 days after the clashes.
The before-and-after images appear to show scores of newly burnt buildings.
"The glaring discrepancies between the facts on the ground and statements by senior military officials raise concerns that they tried to cover up military abuses," the group added.
"Saw soldiers carrying out shootings"
The Red Cross has said that 187 people were killed in the fighting, while an area senator put the death toll at 228.
President Jonathan with a committee recently convened to look into the security challenges in northern Nigeria
In an interview with DW, Eric Guttschuss, HRW researcher on Nigeria, said residents had told them there was heavy gunfire on the night of the attack.
"Some residents said they saw soldiers carrying out shootings, including a woman who said she saw soldiers come into her community, drag a man out of a nearby house, start beating him and when he tried to run, they shot him. She saw the soldiers beat other men within her neighborhood before she fled with her two children into the bush," Guttschuss said.
He added that there needs to be "an independent and impartial investigation into these very serious allegations."
According to HRW, Baga residents said the military warned them they were not cooperating enough in identifying Boko Haram members. If they did not cooperate, then they would be treated as if they were Boko Haram.
Call to the International Criminal Court
But the Nigerian military has fiercely denied claims that soldiers fired on civilians or deliberately torched scores of homes.
After meeting with senior military officials tasked with probing the carnage, President Goodluck Jonathan said Tuesday that "there is a lot of misinformation being peddled about the situation." He said the reported death tolls "cannot be substantiated," and said it was impossible that more than 1,000 homes were destroyed.
But on Wednesday, Jonathan promised to punish any soldier found guilty of misconduct during the deadly raid.
HRW has called on the International Criminal Court to probe the events in Baga as part of the preliminary investigation the court launched in 2010.
The group has previously said that Nigeria's military may have committed crimes against humanity in campaigns against Boko Haram since the insurgency started in 2009.
It wants the incident in Baga to be added to the prosecutor's preliminary investigation.
The group also offered a new death toll for the Boko Haram conflict, saying 3,600 people have lost their lives since 2009, including killings by the security forces.
Boko Haram has said it wants its imprisoned members freed and strict Shariah law adopted across the multiethnic nation of 160 million.
A previous toll last year said the insurgency had cost 3,000 lives.