The unanimous statement followed a closed-door council meeting on Wednesday during which US diplomats said they needed more time to consult with Washington on the proposed text.

Council members "stressed the need for all parties to urgently de-escalate the situation and to commit to a ceasefire," said the statement.

The strike late Tuesday on the Tajoura detention camp east of Tripoli killed 53 people and wounded 130.

The British-drafted text condemned the attack, called for a return to political talks and for full respect of the arms embargo on Libya.

The United Nations has called for an independent investigation to determine who was responsible for the strike on the center, which housed some 600 migrants, mainly from African countries.

UN Secretary-General Antonio Guterres has expressed outrage over the attack and said the United Nations had shared the coordinates of the detention center with the warring sides to protect the civilians.

Libya's Government of National Accord has blamed rival Khalifa Haftar for the attack, but the military leader has denied involvement.

The World Health Organization said Friday that about 1,000 people have died since Haftar launched an offensive in April to seize Tripoli, seat of a UN-recognized government which is supported by various militias.

World powers have been divided about how to respond to Haftar's offensive, with the United States and Russia refusing to criticise the commander whose forces hold eastern Libya and much of the country's south.

Fighting has forced more than 100,000 people to flee their homes and threatens to plunge Libya deeper into conflict.

The north African country has been in chaos, divided by rival administrations in Tripoli and the east, since the 2011 ouster of Moamer Kadhafi.