TRIPOLI, July 3 (Xinhua) -- An airstrike hit a center for migrants late Tuesday in a suburb of the Libyan capital Tripoli, leaving at least 40 people dead, according to health authorities.

Malek Mersek, spokesman for the UN-backed government's health ministry, said early Wednesday that 40 people have been killed so far and around 80 others injured in a strike on a detention center in Tripoli's Tajoura neighborhood.

Tajoura, about 15 km east of Tripoli's downtown, is on the Mediterranean coast. Further details of the strike remained unknown.

Shortly after the strike, the Tripoli-based government issued a statement blaming the Libyan National Army (LNA), led by Khalifa Hafta, for the deadly attack. The east-based LNA has been leading a military campaign since April to try to take over Tripoli.

The United Nations Refugee Agency (UNHCR) expressed concerns about the strike. "Civilians should never be a target," UNHCR Libya wrote on its Twitter page.

Libya is a main departure place for undocumented migrants from African and Arab countries trying to reach Europe by sea, but many of them were stopped by the Libyan coast guards funded by the European Union and detained in detention centers in Libya.