MOSCOW — Diplomatic efforts to end the conflict in Libya ratcheted up on Tuesday as Russia claimed that the warring factions had agreed to maintain a fragile ceasefire and Germany announced an international summit on the crisis this Sunday.

Libyan strongman Khalifa Haftar left talks in Moscow on Tuesday without signing a permanent truce aimed at ending nine months of fighting, though Russia claimed he agreed to maintain the current cease-fire.

Berlin then announced it had invited both sides of the Libyan conflict to talks with 11 countries and several international organizations on Sunday.

Haftar and his allies were in Moscow on Monday for discussions with the United Nations-recognized government headed by Fayez Al-Sarraj that is based in Tripoli.

The meetings raised hopes of an end to the latest fighting to wrack Libya since a 2011 NATO-backed uprising killed dictator Muammar Gadhafi.

But Haftar's abrupt departure from Moscow marked a setback.

Playing down the blow, Russia's defense ministry said Haftar had asked for two days to consider the deal, stressing that a shaky cease-fire established at the weekend would continue.

Russia's Foreign Minister Sergei Lavrov also promised to "pursue efforts" to mediate.

But Turkish President Recep Tayyip Erdogan reacted angrily, warning that "we will not hesitate to teach the putschist Haftar a deserved lesson ... if he continues his attacks on Libya's legitimate administration and our brothers in Libya".

Erdogan said the issue would be discussed in Berlin on Sunday by European, North African and Middle Eastern countries as well as the the UN, the EU, the African Union and the Arab League.

"The putschist Haftar did not sign the cease-fire. He first said yes, but later unfortunately he left Moscow, he fled Moscow," Erdogan said, while praising "positive" talks.

Anxious to calm flaring tempers, Berlin called a UN-sponsored summit of 11 countries — including the USA, Russia, China and Turkey.

It remained unclear whether Haftar and Sarraj would also attend, though Berlin said both had been invited.

According to a source close to the discussions, a key aim of the summit will be to help Libya "sort out its problems without foreign influence".

Western powers are keen to stabilize Libya — home to Africa's largest proven crude reserves — following years of turbulence since the 2011 killing of Gadhafi.

Sarraj's government has been under attack since April from forces loyal to Haftar, who is based in the east of the oil-rich North African country with his own loyalist politicians.

Since the start of the offensive against Tripoli, more than 280 civilians and 2,000 fighters have been killed and 146,000 Libyans displaced, according to the United Nations.

The clashes have also spurred a growing exodus of migrants from Libya, though nearly 1,000 intercepted at sea have been forced to return this year, according to the UN.

Putin and Erdogan made a joint call for a cease-fire, which started early Sunday and was welcomed by the UN.

Putin later Monday discussed the talks with German Chancellor Angela Merkel.

Turkey and Russia's diplomatic initiative came despite the countries being seen as supporting opposing sides.

Ankara dispatched troops — in a training capacity, it said — to support the GNA in January in a move criticized by European powers and US President Donald Trump.

The GNA has signed agreements with Ankara assigning Turkey rights over a vast area of the gas-rich eastern Mediterranean, in a deal denounced by France, Greece, Egypt and Cyprus.