A Libyan boy looks at a destroyed building after an airstrike in east of Tripoli, Libya, Dec. 29, 2019. A civilian was killed and two others were injured on Sunday when an airstrike hit east of the Libyan capital Tripoli, according to a medical official.(Photo: Xinhua)

 A civilian was killed and two others were injured on Sunday when an airstrike hit east of the Libyan capital Tripoli, according to a medical official.

Osama Ali, spokesman of Health Ministry's Emergency Department, said the airstrike hit a residential area in eastern Tripoli, killing a woman and injuring two foreign workers.

The casualties of the airstrike are likely to increase as medical emergency teams are still carrying out rescue operations in the area, the spokesman said.

The eastern-based army has been launching a military offensive since April in an attempt to take over the capital Tripoli from the rival UN-backed government.

Thousands have been killed and injured in the fighting, while more than 120,000 civilians have been displaced.

On Saturday, UN Special Envoy to Libya Ghassan Salame condemned continued airstrikes on civilians in western Libya.

"Indiscriminate attacks against civilians not only constitute a grave violation of international humanitarian law and human rights law, but also further escalate the conflict and incite future acts of revenge, which threaten the social unity in Libya. This is utterly unacceptable," Salame said in a statement.

According to the UN Support Mission in Libya and the UN Higher Commission of Refugees, at least 284 civilians were killed and 363 others injured during 2019, besides casualties caused by recent airstrikes in Tripoli and the city of Zawiya, some 45 km west of Tripoli.