Militias in control of the Libyan capital have rejected the United Nations' call for a ceasefire, insisting instead that their rivals be disarmed.
The announcement by the Libya Dawn umbrella group on Tuesday followed the first round of UN-brokered talks between Libya's rival lawmakers held on Monday in Ghadames, a southern town near the Algerian border.
The talks are an attempt to bridge the gap between warring groups that have left Libya torn between two rival governments and parliaments.
Libya Dawn, which controls Tripoli and which is affiliated with the militia from the western city of Misrata, said on its Facebook page on Tuesday that the only way to end the fighting is to disarm its rivals and arrest their leaders.
The statement is a setback for the UN-mediated talks and reflects deep polarisation in Libya, which has been plunged into its worst turmoil since the 2011 NATO-backed uprising that toppled longtime dictator Muammar Gaddafi.
The 2011 revolt gave rise to a patchwork of heavily armed and increasingly unruly militias.
The current crisis is rooted in the successive Libyan governments' dependence on those militias, originally anti-Gaddafi rebel forces, in restoring order in the absence of a strong national army or police.
The recent Islamists' takeover of Tripoli followed weeks of fighting that forced nearly a quarter million Libyans to flee their homes and prompted an exodus of diplomats and foreigners from the city. Once in control of the capital, the militias revived the country's outgoing parliament, dominated by Islamist lawmakers.
Meanwhile, Libya's elected - and internationally recognised parliament - based in the eastern city of Tobruk wields little influence beyond that city's boundaries.
Earlier, the Tobruk-based parliament denounced the Libya Dawn, saying the assault on Tripoli is an act of terrorism and passing a resolution to disarm militias controlling the capital.