Kurds from the Syrian Democratic Forces (SDF) have withdrawn to 32 kilometers (20 miles) away from the border with Turkey, Russia's RIA news agency reported on Thursday, citing an SDF official.

Kurdish forces have begun withdrawing from areas near the Turkish frontier in Syria, Russia's deputy foreign minister also said, following a deal between Moscow and Ankara that ended Turkey's cross-border military offensive. 

Under Tuesday's accord, sealed by presidents Vladimir Putin and Tayyip Erdogan in the Russian city of Sochi, Russian military police and Syrian border guards are required to remove all Kurdish YPG militia 30 kilometers (19 miles) from the Turkish border over a roughly six-day period.

Ankara views the YPG as terrorists with ties to Kurdish insurgents operating in southeast Turkey.

"We note with satisfaction that the agreements reached in Sochi are being implemented," Russian Deputy Foreign Minister Sergei Vershinin said. "Everything is being implemented."

Russia will send a further 276 military policemen and 33 units of military hardware to Syria in a week to help implement the deal, RIA news agency cited a defense ministry source as saying. The first Russian military police arrived in the northern Syrian town of Kobani on Wednesday.

Next Tuesday, Russian and Turkish forces will start to patrol a 10 km strip of land in northeast Syria where U.S. troops had for years been deployed along with their former Kurdish allies.

Asked whether there would be joint patrols with the Russians or separate coordinated patrols, Turkish security sources said on Thursday Ankara was still working on the issue and that the 150-hour period set for the YPG to withdraw had only just begun.

Pivot to Russia 

The arrival of the Russian police marks a shift in the regional balance of power just two weeks after U.S. President Donald Trump pulled out U.S. special forces, a move criticized in Washington and elsewhere as a betrayal of the Kurds.

Turkish troops and their Syrian rebel allies subsequently launched an offensive into northeast Syria against the YPG.

It "paused" the offensive last week under a U.S.-brokered ceasefire that called for YPG fighters to withdraw and then secured Russian support in Sochi for a wider deal requiring the YPG's removal from the whole northeast border.

Trump said Wednesday that the ceasefire was now permanent and lifted sanctions imposed on Turkey over its offensive.

The Turkish public has shown strong support for the military operation, according to the results of an opinion poll published by pollster Areda Survey last week.

A Turkish security official said on Thursday that Turkey was currently training personnel on the S-400s and that the April 2020 timeline was still in place.

U.S.: Turkey 'heading in the wrong direction' over Syria

Turkey is "heading in the wrong direction" with its incursion into Syria and deal with Russia to jointly patrol a "safe zone" there, U.S. Defense Secretary Mark Esper said Thursday.

"Turkey put us all in a very terrible situation" by sweeping into northern Syria this month to fight Kurdish militia allied with the U.S. in the fight against the Islamic State group, Esper told a conference in Brussels ahead of a NATO defense ministers' meeting.

The onus was on Turkey's NATO allies to now "work together to strengthen our partnership with them, and get them on the trend back to being the strong, reliable ally of the past," he said.

Yet, while isolated in NATO, Turkey's strategic position between Europe and the Middle East is seen as too important to jeopardize, so the other alliance members have limited themselves to criticism only.

Esper defended the U.S.'s decision to abandon its Kurdish ally and pull U.S. forces out of northern Syria, which was widely criticized both domestically and internationally, giving Ankara a free hand to launch its long-prepared operation.  

(Input from agencies)