UNITED NATIONS (Reuters) - The United Nations Security Council will on Tuesday discuss Turkey’s shelling of targets in Syria at the request of Russia, which has voiced concern about Turkish military attacks on Russian-backed Kurdish militia fighters, according to an email exchange.

Turkey shelled Kurdish YPG positions for a third straight day to try to stop its fighters from seizing Azaz, just 8 km (5 miles) from the border. Ankara fears the YPG, backed by Russia, are trying to secure the last stretch of around 100 km along the Syrian border not already under its control.

“The Russian delegation is deeply concerned by the use of force by Turkey against the Syrian territory,” a Russian diplomat said in an emailed request for the meeting sent on Monday to other council diplomats. Reuters saw the email exchange.

A senior U.N. official is expected to brief the council on the situation in Syria early on Tuesday. The closed-door discussion is expected to take place in the morning after the council discusses the humanitarian situation in Yemen.

The international standoff over Syria has increased the risk of direct confrontation between Russia and NATO member Turkey. Relations between Moscow and Ankara deteriorated sharply after the Turkish military shot down a Russian warplane in November along the Turkish-Syrian border.

The Syrian civil war, reshaped by Russia’s intervention last September, has gone into an even higher gear since the United Nations sought to revive peace talks. These talks were suspended earlier this month in Geneva before they got off the ground.