Haftar’s abrupt departure early Tuesday was a setback for an international diplomatic push in recent days, though Moscow insisted it would continue mediation efforts.
Haftar and his allies were in Moscow on Monday for talks with the U.N.-recognized government headed by Fayez al-Sarraj.
Based east of the oil-rich North African country and backed by loyalist politicians, Haftar forces have been attacking Sarraj's government since last April.
The two sides agreed to a cease-fire brokered by Russia and Turkey that took effect over the weekend and were in Moscow to sign a long-term agreement to bring an end to the nine months of clashes.
The talks raised hopes for an end to the latest fighting to wrack Libya since a 2011 NATO-backed uprising killed longtime dictator Muammar Gaddafi.
But after seven hours of negotiations, only Sarraj had signed the agreement, and Russian officials confirmed that Haftar's delegation had left without signing the deal.
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