The death toll from rocket fire on the Libyan capital Tripoli, blamed by the UN-recognised government on strongman Khalifa Haftar, climbed to six on Wednesday as thousands more civilians fled the violence.
The latest bombing came as world powers wrangled over the wording of a UN Security Council resolution demanding a ceasefire, with Russia blocking criticism of Haftar, according to diplomats.
Three of the six killed in the rocket fire on the southern Tripoli neighbourhoods of Abu Salim and Al-Antisar late on Tuesday were women, said the UN's humanitarian coordination agency, OCHA.
Abu Salim mayor Abdelrahman al-Hamdi confirmed the death toll and said 35 other people were wounded.
AFP journalists heard seven loud explosions as rockets hit the city centre, the first since Haftar's Libyan National Army militia launched an offensive on April 4 to capture Tripoli from the government and its militia allies.
The LNA blamed the rocket fire on the "terrorist militias" whose grip on the capital it says it is fighting to end.
UN envoy Ghassan Salame condemned "in the strongest terms" the overnight shelling, spokesman Stephane Dujarric said.
He added that "responsibility for actions that may constitute war crimes lies not only with the individuals who committed the indiscriminate attacks, but also potentially those who ordered them."
The bombardment came as diplomats at the UN Security Council debated a British-drafted resolution that would demand an immediate ceasefire in Libya.
The proposed text, seen by AFP, warns the Haftar offensive "threatens... prospects for a United Nations-facilitated political dialogue and a comprehensive political solution to the crisis."
- No Haftar criticism -
After Britain circulated the text late Monday, diplomats held a first round of negotiations in which Russia raised objections to references criticising Haftar, diplomats said.
"They were very clear. No reference anywhere," a council diplomat said.
During a tour of the Tripoli neighbourhoods worst hit by the rocket fire on Tuesday night, unity government head Fayez al-Sarraj said the Security Council must hold Haftar to account for his forces' "savagery and barbarism".
"It's the legal and humanitarian responsibility of the Security Council and the international community to hold this criminal responsible for his actions," Sarraj said in footage of the tour released by his office.
He said his government would seek Haftar's prosecution for war crimes by the International Criminal Court in The Hague.
"We are going to hand all the documentation to the ICC tomorrow (Wednesday) for a prosecution for war crimes and crimes against humanity," he said.
At least 189 people have been killed and 816 wounded since Haftar ordered his forces to march on Tripoli, according to the World Health Organization.
More than 25,000 people have been displaced, including 4,500 over the last 24 hours, the International Organization for Migration said.
Britain was hoping to bring the ceasefire resolution to a vote at the Security Council before Friday, but diplomats pointed to Russia's objections as a hurdle.
As consultations continued in New York on Wednesday, Russia's deputy UN ambassador Dmitry Polyansky told reporters "we need to have a nice document" but declined to give details on the areas of disagreement.
Asked if the draft could be adopted this week, he said: "It depends on them, not us," without elaborating.
- Proxy war -
Haftar, seen by other allies Egypt and the United Arab Emirates as a bulwark against Islamists, has declared he wants to seize the capital.
He backs a rival administration based in eastern Libya that is refusing to recognise the authority of the Tripoli government.
The draft resolution calls on all sides in Libya "immediately to recommit" to UN peace efforts and urges all member states "to use their influence over the parties" to see that the resolution is respected.
Resolutions adopted by the council are legally binding.
Diplomats have long complained that foreign powers backing rival sides in Libya threatened to turn the conflict into a proxy war.
Saudi Arabia is also seen as a key Haftar supporter, while Qatar -- which has tense relations with Riyadh and Abu Dhabi -- has called for stronger enforcement of the UN arms embargo to keep weapons out of Haftar's hands.
Russia and France, two veto-wielding permanent members of the Security Council, have praised Haftar's battlefield successes in defeating militias aligned with the Islamic State group in the south of the country.
Haftar's offensive forced the UN to postpone a national conference that was to draw up a roadmap to elections, meant to turn the page on years of chaos since the 2011 ouster and Moamer Kadhafi in a NATO-backed rebellion.
Guterres has said serious negotiations on Libya's future cannot resume without a ceasefire.