A Turkish-backed Free Syrian Army fighter carries a military binoculars north of the city of Afrin, Syria, Feb. 18, 2018. Photo: Reuters / Khalil Ashawi.

Militias allied to the Syrian government will enter the Afrin region, Syrian media reported on Monday, after a Kurdish official said a deal had been struck with the Syrian army to help Kurdish forces end a Turkish offensive.

Turkey said it would welcome any move by Damascus into Afrin to get rid of the YPG Kurdish militia, but if Syrian troops were entering to protect the Kurdish fighters, then the Turkish assault would go on.

A second Syrian Kurdish official said no pro-government military forces were arriving in Afrin on Monday. While the deal was supposed to have been announced formally on Monday, the source said, external pressure might prevent it going ahead.

Turkey began its operation last month with allied Syrian rebel groups to drive out the YPG, which Ankara regards as a terrorist group linked to an insurgency at home and sees as a security threat to its border.

That offensive further complicated the web of rivalries and alliances in northern Syria among Kurdish forces, the Syrian government, rebel factions, Turkey, Iran, the United States and Russia.

But on Sunday, a senior Syrian Kurdish official said Kurdish forces and the Syrian government had reached a deal for the Syrian army to enter Afrin, and that it could be implemented within two days.

All deals between the Syrian government and the Kurds, which each hold more territory than any other side in Syria, are closely watched because they could prove pivotal for the future course of the war.

While President Bashar al-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.

“Popular forces will arrive in Afrin in the next few hours to support the steadfastness of its people in confronting the aggression,” state news agency SANA reported, citing its correspondent in Aleppo, 35 kilometers (22 miles) from Afrin.

Badran Jia Kurd, an adviser to the Kurdish-led autonomous administration that runs swathes of northern Syria, told Reuters Syrian army troops would deploy along some border positions under the deal between the Kurds and the government.

The deal was only on military aspects and any political or other agreements would have to wait for further negotiations between Damascus and the Kurdish administration, he said.

There was some opposition to the deal that could stand in its way, he added.

Turkish Foreign Minister Mevlut Cavusoglu said on Monday: “If the regime is entering there to cleanse the PKK and PYD, then there are no problems.” The PKK is the Kurdish group mounting an insurgency in Turkey. The PYD is an influential Syrian Kurdish political party.

But, speaking at a news conference in Jordan, he added: “If it comes in to defend the YPG, then nothing and nobody can stop us or Turkish soldiers.”

The Afrin offensive has put strains on 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, causing widespread anger in 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 alliance of militias of which the YPG is a major part.

The Syrian government was not immediately available for comment on Monday.