A Turkish strike hit a Kurdish position inside a Russian base in Syria Wednesday killing a fighter, a Kurdish official said, as Turkey pressed an air offensive against Kurdish targets in Syria and Iraq.

The drone strike also wounded three fighters of the Kurdish-led Syrian Democratic Forces, a key ally of the US-led coalition battling the Islamic State group in the region, SDF official Farhad Shami said.

Britain-based war monitor the Syrian Observatory for Human Rights said a Russian soldier was also wounded in the strike, which came a day after a similar deadly strike on another base in northeastern Syria that is used by the US-led coalition.

There was no immediate confirmation from Moscow.

Russia has had troops in Syria since it intervened in support of President Bashar al-Assad in 2015.

Its main bases lie in the northwest but since 2019 it has also had troops in northeastern Syria acting as a buffer between Turkish and Kurdish forces.

Turkish Defence Minister Hulusi Akar said Wednesday that Turkish forces had hit nearly 500 Kurdish targets across Iraq and Syria since Sunday as part of Operation Claw-Sword, an offensive Ankara says it launched in retaliation for a deadly bombing in Istanbul earlier this month.

Turkish President Recep Tayyip Erdogan has blamed the November 13 bombing on the outlawed Kurdistan Workers' Party (PKK), which operates rear-bases in northern Iraq.

On Monday, he renewed a longstanding threat to launch a cross-border ground operation into SDF-controlled areas of northeastern Syria, drawing calls for restraint from both Moscow and Washington.

The SDF is dominated by the Kurdish People's Protection Units (YPG), which is regarded as a "terrorist" group by Ankara for its alleged links to the PKK.

Turkish artillery carried out heavy shelling on Wednesday of the area around the jail in the border city of Qamishli where Islamic State group prisoners are held, the SDF official and the Observatory said.

The monitoring group also reported Turkish drone strikes against four oil or gas facilities in Hasakeh province, including a gas refinery and an oil pumping station.