By Angus McDowall and Tuvan Gumrukcu
BEIRUT/ANKARA (Reuters) - Turkey warned on Monday it would confront Syrian government forces if they entered Syria's northwestern Afrin region to help the Kurdish YPG militia repel a Turkish offensive.
Turkey began its Afrin operation with allied Syrian rebels last month against the YPG, which Ankara sees as a threat along its border with links to the Kurdish PKK insurgency at home.
Ankara's onslaught has further scrambled the matrix of rivalries and alliances in northern Syria among Kurdish forces, the Syrian government, insurgent factions, Turkey, Iran, the United States and Russia.
Monday's comments by Turkey's president and foreign minister came after a senior Kurdish official said on Sunday that a deal had been struck for Syrian army to go into Afrin soon to help fight the assault.
But YPG spokesman Nouri Mahmoud denied on Monday reaching such an agreement with the Damascus government.
Syrian state media said in the morning that pro-government militia would enter Afrin "within hours" but by sunset there were no signs of a deployment there.
"If (the Syrian army) comes in to defend the YPG, then nothing and nobody can stop Turkish soldiers," Turkish Foreign Minister Mevlut Cavusoglu said in Jordan. Turkey would have no issue with Syrian troops entering Afrin if they did so to "cleanse" it of the Kurdish fighters, he added.
Turkish President Tayyip Erdogan later said in a phone call with Russian President Vladimir Putin that Damascus would face consequences if it struck a deal with the YPG and said the Afrin operation would continue, CNN Turk reported.
There was no immediate comment from the Syrian military or from Moscow.
Erdogan also spoke to Iranian President Hassan Rouhani about developments in Syria's Idlib and Afrin, a Turkish source said.
Badran Jia Kurd, an adviser to the Kurdish-led autonomous administration in north Syria, said on Sunday there was a military understanding between Damascus and Kurdish forces for the Syrian army to enter Afrin. But he added that it faced opposition which could derail it.
Another Syrian Kurdish political official said on Monday that pressure from Russia, the key ally of Syrian President Bashar al-Assad, had prevented the deal from going ahead so far.
YPG spokesman Nouri Mahmoud said there was only "a call from us for the Syrian army to come in and protect the borders.
"This is its duty," he said. "So far, the Syrian army has not fulfilled its duty towards Afrin."
Deals between the Syrian government and the Kurdish forces, which each hold more territory than any other side in Syria, could prove pivotal for the future course of the war.
Since the onset of Syria's conflict in 2011, the YPG and its allies have set up three autonomous cantons in the north, including Afrin bordering Turkey. Their sphere of influence expanded as they seized territory from Islamic State militants with U.S. help, though Washington opposes their political ambitions as does the Syrian government.
While Assad's government and the YPG espouse different visions for Syria's future and their forces have clashed at times, they have mostly avoided direct conflict.
Jia Kurd told Reuters on Sunday that Syrian army troops would deploy along some border positions under the deal between the Kurdish fighters and Damascus. He said the deal was only on military aspects and any political or other agreements would have to wait for further talks.
"Popular forces will arrive in Afrin in the next few hours to support the steadfastness of its people in confronting the aggression," Syrian state news agency SANA said earlier.
Ankara regards the YPG as indistinguishable from the PKK, though the groups say they are independent from each other. Turkey, the United States, and Europe classify the PKK, a leftist Kurdish movement that has mounted a three-decade insurgency inside Turkey, as a terrorist organization.
The Afrin offensive has strained the complex ties between the warring sides in northern Syria and their external supporters.
Turkey's NATO ally the United States has armed the YPG as part of an alliance it backs in Syria against Islamic State, which has infuriated Ankara.
But while Washington has a military presence in the much larger swathes of Syria that the YPG and its allies control further east, it has not given support to the YPG in Afrin.
This month, the United States said it had killed hundreds of pro-government troops in strikes in eastern Syria because they were attacking the militia alliance which the YPG spearheads.
(Reporting by Lisa Barrington and Ellen Francis in Beirut, Rodi Said in northern Syria, Suleiman al-Khalidi in Amman, Tuvan Gumrukcu, Ece Toksabay and Tulay Karadeniz in Ankara; writing by Angus McDowall; editing by Mark Heinrich)