Egypt failed to "take necessary precautions" to protect civilians when it launched air strikes in Libya following the murders of 21 Egyptian Christian hostages earlier this month, a human rights group says.

Amnesty International released eyewitness testimonies late on Monday about a strike which killed seven civilians in the eastern Libyan city of Derna on February 16.

At the time, Egypt's military said it carried out the raids against Islamic State of Iraq and the Levant (ISIL) camps, training sites and weapons storage areas.

The strikes came hours after fighters pledging allegiance to ISIL released a video purporting to show the killing of the Egyptians kidnapped in Libya. In a statement aired on state television, the military said: "The air strikes hit their [ISIL] targets precisely, and the falcons of our air forces returned safely to their bases."

However, photos published on social media showed several damaged residential areas in Derna and seven civilians were killed, including three children.

Amnesty said witnesses told them that the last strike, which took place at around 7:15am, "targeted a civilian area in Sheiha al-Gharbiya" neighbourhood.

"One missile struck a four-storey house belonging to the al-Kharshoufi family, killing a mother and her three children aged between three and eight, and injuring their father and another child," Amnesty's statement said.

"A second missile hit a street in between civilian houses, causing three other deaths."

Response 'disproportionate'

Hassiba Hadj Sahraoui, Amnesty's Middle East and North Africa Deputy Director, said "the killing of seven civilians, six of them in their own homes, must be investigated, as it appears to have been disproportionate".

"The Egyptian authorities must publicly disclose detailed information on all air strikes carried out in Derna on 16 February, including targets, and measures taken to avoid incidental harm to civilians," he said.

"Even if the Egyptian military believed that fighters were present in the house or in the vicinity, they should have taken the necessary precaution to identify who else was in the house and in the neighbourhood to avoid or at least minimise civilian casualties."

Libya has slid into chaos after Muammar Gaddafi was overthrown and killed three years ago, as interim authorities failed to confront powerful militias which fought to oust the longtime leader.

Taking advantage of the chaos, ISIL has carried out a string of deadly attacks.

Source: Al Jazeera