NEW YORK - UN human rights chief Michelle Bachelet has warned that attacks on civilians in Libya could amount to war crimes.

She urged all sides to avoid bloodshed as military strongman Khalifa Haftar's forces advance on the UN-recognised government in Tripoli.

Some 47 people have been killed over the past three days, says the World Health Organization (WHO), as his forces seek to capture the capital.

On Monday, an air strike closed the city's only functioning airport.

The UN's special envoy to Libya, Ghassan Salame, hinted that a peace conference due to start this Sunday could be postponed, saying it would be convened "as soon as possible".

Libya has been torn by violence, political instability and power struggles since long-time ruler Muammar Gaddafi was deposed and killed in 2011.

The rights commissioner said that the people of Libya "have long been caught between numerous warring parties, with some of the most vulnerable suffering some of the gravest violations of their human rights".

She said: "The attack near Mitiga airport [on Monday] that left many civilians in Tripoli stranded brought into stark focus the imperative for all parties to respect international humanitarian law, and to take all possible measures to protect civilians and civilian infrastructure, including schools, hospitals and prisons."

As well as the 47 deaths, 181 people were said to have been injured in recent clashes, the WHO said.

That was a higher toll than numbers given by either side, and appeared to be mainly fighters, it said.

Nine of the dead were civilians, including two doctors who it said had been "providing critically needed services to civilians in Tripoli. One doctor was reportedly killed while working as part of a field ambulance service".

The WHO said it had documented more than 40 attacks on health services in Libya over the course of 2018 and 2019. Targeted attacks on health services were a violation of international law, the organisation said.

At least 2,800 people have so far fled fighting around Tripoli, the UN says.

It also warns that those who remain risk being cut off from vital services because of the clashes.(FA)