Migrants who survived the deadly airstrike on a Libyan detention center said Thursday they had been conscripted by a local militia to work in an adjacent weapons workshop and were shot at as they tried to flee.

The decision to store weapons at the facility in Tajoura, to the east of Tripoli, may have made it a target for the self-styled Libyan National Army (LNA), which is at war with an array of militias allied with a weak, UN-recognised government in the capital.

The Tripoli government has blamed Wednesday's pre-dawn strike, which killed at least 53 migrants and wounded more than 130, on the LNA and its foreign backers.

The LNA, led by General Khalifa Haftar, says it targeted a nearby militia position but denies striking the hangar where the migrants were being held.

Gen Haftar, whose forces control much of eastern and southern Libya, has received aid from Egypt, the United Arab Emirates, Saudi Arabia and Russia. The UN said on Thursday it had information that Libyan guards shot at refugees and migrants trying to flee from the air strikes.

"There are reports that following the first impact, some refugees and migrants were fired upon by guards as they tried to escape," a report released by the Office for Coordination of Humanitarian Affairs said.