(CNN)The two sides battling for control of the Libyan capital Tripoli have engaged in "shameful" attacks on civilian neighborhoods that could amount to war crimes, Amnesty International said.
Renegade Field Marshal Khalifa Haftar, who has been praised by President Donald Trump, commands the Libyan National Army, which in April began an offensive to seize the city from the United Nations-backed Government of National Accord.
Libya has been plagued by violence since the ouster and killing of longtime strongman Moammar Gadhafi in 2011.
More than 400 people have been killed in the latest offensive and over 2,000 wounded, according to the World Health Organization. The UN's humanitarian affairs office said more than 60,000 people have fled their homes.
Trump was strongly criticized for praising Haftar last month as his forces moved in on the capital. The White House's official readout of a phone call between Trump and Haftar, who holds US citizenship, made no mention of the offensive on Tripoli, which Secretary of State Mike Pompeo had criticized earlier in April.
"As the battle for Tripoli unfolds, the warring parties have displayed a shameful disregard for civilian safety and international humanitarian law by carrying out indiscriminate attacks on residential neighborhoods," said Magdalena Mughrabi, Amnesty International's deputy Middle East and North Africa deputy director.
"Such reckless attacks could have devastating consequences for civilians and strengthen the need for the International Criminal Court to expand its investigations into possible war crimes by all sides in Libya's conflict."
Amnesty International said satellite images and witness testimony indicated that "densely populated residential areas in the Abu Salim district of Tripoli were indiscriminately attacked with rockets during an episode of intense fighting between 15-17 April."
Haftar's forces and a local militia affiliated with the Government of National Accord blamed each other for the indiscriminate attacks in southern Tripoli. Residents interviewed by Amnesty International told the NGO they believed Haftar's forces were responsible.
"Deliberate attacks on civilians and civilian property, and indiscriminate attacks that kill or injure civilians, amount to war crimes. All sides have an absolute obligation under international law to protect civilian lives and to clearly distinguish between civilians and fighters during their attacks," Mughrabi said.
Haftar took part in the coup that brought Gadhafi to power 50 years ago. Now in his mid-70s, he has sent his forces across the desert from Benghazi in a bid to seize the country for himself.
Haftar's main supporters are Saudi Arabia, Egypt and the United Arab Emirates.
The Government of National Accord has the recognition of the United Nations but has difficulty enforcing its rule beyond the capital. It is hobbled by internal feuds and depends for security on rival militia, most of whom have an Islamist complexion.