According to reports, at least 42 people have died in a drone strike that hit a town hall meeting in the town of Murzuq in south-western Libya carried out by the forces of the Libya National Army (LNA). Gen Haftar's forces stated that they targeted the town late on Sunday, but denied targeting civilians.
The airstrike left "42 dead and more than 60 injured, 30 of them critically" at the town hall in Qalaa neighbourhood, where more than 200 people were at a meeting "to settle social differences", council official Ibrahim Omar told AFP news agency.
Local media had conflicting reports earlier saying that the strike had allegedly hit a wedding party.
The UN-backed Government of National Accord (GNA) condemned the attack on social media and accused Gen Haftar's forces of carrying it out. It also urged the UN to "carry out an investigation into the crimes committed by Haftar's militias in Murzuq".
Pro-Haftar media outlets said the attack had targeted Chadian mercenaries, which is how they refer to the Tebu ethnic group which opposes Gen Haftar in the oil-rich southern part of the country.
This is the second time in two months that an air strike thought to be by Gen Haftar's forces has resulted in mass civilian casualties. In June, some 44 people were killed in a migrant detention centre on the outskirts of Tripoli.
Months of fighting between the GNA and Mr Haftar's forces has claimed more than 1,000 lives since April, according to the World Health Organisation (WHO).