Leading human rights organization Amnesty International has demanded NATO investigate allegations it killed 85 Libyan civilians during airstrikes.
The Libyan government has accused NATO of killing 85 civilians, including 33 children, during airstrikes on Monday against forces supporting Muammar Gaddafi in the civil war that has engulfed the country since a violent government crackdown on anti-regime protestors in February.
It was alleged the civilians in the western part of the country were killed to help clear the way for rebels advancing on the Gaddafi-controlled city of Zlitan, CNN reports.
"NATO continues to stress its commitment to protect civilians. To that effect, it should thoroughly investigate this and all other recent incidents in which civilians were reportedly killed in western Libya as a result of air strikes," Hassiba Hadj Sahraoui of Amnesty International said in a statement on Wednesday.
But NATO - which began its bombing campaign against Gaddafi's forces in March after U.N. Security Council resolution - has said it does not have evidence of civilian casualties.
Gaddafi has called it an "ugly massacre by NATO", AFP reports.
NATO has come under fire in recent months by some human rights groups and foreign countries for reportedly errant air strikes that have resulted in civilians being killed.
Amnesty International urged NATO to take necessary precautions to avoid civilian casualties.
On Monday, government officials escorted international journalists to a mass funeral in Majer, and to the site where the government alleges an airstrike killed civilians.
It was impossible for CNN to confirm the extent of the casualties, and whether they were all civilians.
For weeks, Zlitan has been the target of an intense NATO bombing campaign. The number of buildings and compounds devastated by airstrikes has visibly increased since international journalists went on a government-controlled tour of the small city in July.
The Gaddafi regime has accused NATO of hitting food warehouses, health clinics and schools. But a tour of one bomb site last week revealed evidence suggesting the target was not entirely civilian.
CNN found several military uniforms lying on the ground next to wooden ammunition crates. When asked about the military paraphernalia, a government escort said the ammo boxes and uniforms "belonged to school security guards."
NATO claims its warplanes struck two farms used as a staging point for Gaddafi's forces.
"This is a legitimate target. And by striking it, NATO has reduced pro-Gadhafi forces capabilities to threaten and attack civilians," said Col. Roland Lavoie, a spokesman for the NATO operation.
"We do not have evidence of civilian casualties at this stage, although casualties among military personnel, including mercenaries, are very likely due to the nature of the target."
This comes as America stepped up its diplomatic offensive against the regime, with diplomats visiting African countries to urge them to demand Gaddafi step down, AFP reports.