Russia says it won't allow clashes between Turkish and Syrian forces as Turkey pressed its offensive against Kurdish forces in northern Syria.
Such a confrontation would be "simply unacceptable," the Kremlin's special envoy for Syria, Aleksandr Lavrentyev said during a visit to the United Arab Emirates on October 15, adding: "We will not let this happen."
Lavrentyev also said that Turkish and Syrian officials are in contact to avoid any clash.
Meanwhile, Russia's Defense Ministry said its troops were patrolling along the front line between Syrian and Turkish forces outside the northern town of Manbij, west of the Euphrates River, to keep them separated, Russian state media reported.
Kelly Craft, the U.S. ambassador to the United Nations, said that Washington was "deeply concerned" about these Russian patrols.
Russia, a key military ally of Syrian President Bashar al-Assad, has deployed troops in the country since 2015.
Turkey launched its offensive last week with the aim of pushing the Kurdish-led Syrian Democratic Forces (SDF) from the border region. Turkey regards the largest militia in the SDF a terrorist organization.
Ankara says it wants to establish a "safe zone" in the area to resettle up to 2 million Syrian refugees currently on Turkish territory.
Kurdish-led forces have announced a deal with the Syrian government for military support to help repel the Turkish assault.
Syrian forces have since taken control of an area of more than 1,000 square kilometers around Manbij, the Russian Defense Ministry was quoted as saying.
The ministry said that the Syrian Army had taken control of the Tabqa military airfield, two hydroelectric power plants, and several bridges across the Euphrates River.
Earlier, the United States imposed sanctions on Turkish ministries and senior government officials in response to the country’s offensive, which came after U.S. President Donald Trump decided to withdraw forces from the area.
The SDF has been a key ally of the United States in the fight against the Islamic State (IS) extremist group in Syria.
U.S. Vice President Mike Pence is set to meet with Turkish President Tayyip Erdogan on October 17 in Ankara, where he will urge Turkey to reach an immediate cease-fire in Syria, the White House said.
Pence "will reiterate President Trump's commitment to maintain punishing economic sanctions on Turkey until a resolution is reached," a statement said.
Trump told reporters that Pence will be accompanied by State Secretary Mike Pompeo, saying the two will leave the United States on October 15.
In the first week of the Turkish offensive, more than 150 SDF fighters have been killed, along with nearly 130 fighters from Turkish-backed Syrian factions, according to the Syrian Observatory for Human Rights. The British-based group said at least 69 civilians were also killed in Syria.
Turkish officials say six of its soldiers have died, as well as at least 20 Turkish civilians killed by Kurdish mortar fire across the Syrian border.
At least 190,000 people have fled their homes in northern Syria, according to the International Organization for Migration (IOM).