The announcement came just hours after Foreign Minister Hakan Fidan discussed the US downing of a Turkish combat drone involved in the Syria operation with Secretary of State Antony Blinken.

The Turkish defence ministry said it had hit 15 Kurdish targets in northern Syria on Friday evening "with the maximum amount" of ammunition.

The targets included "headquarters and shelters" used by Kurdish forces that the United States has relied on to fight the Islamic State group in Syria.

Fidan told Blinken that Ankara's air strikes in Syria will continue "with determination" despite Thursday's drone episode -- the first of its kind between the strategic NATO allies.

Turkey stepped up cross-border air raids against Kurdish targets in northeastern Syria and northern Iraq in retaliation for a bombing in Ankara that injured two policemen last Sunday.

A branch of the Kurdistan Workers' Party (PKK) -- listed as a terror group by Ankara and its Western allies -- claimed responsibility for the first bombing to hit the Turkish capital since 2016.

Turkey concluded that the two assailants who died in the Ankara attack came from Syria.

Turkey's operation in Syria has primarily been targeting oil and other energy facilities controlled by the Kurdish People's Protection Units (YPG).

The group comprises an integral part of the US-backed Syrian Democratic Forces (SDF) -- the Kurds' de facto army in the area -- that spearheaded the battle to dislodge Islamic State group jihadists from the region in 2019.

The SDF said Friday that eight civilians were among the 15 people confirmed killed in the first two days of Turkey's strikes.

United States support for the YPG has strained Ankara's ties with Washington since the jihadists' defeat.

Washington said an F-16 jet shot down the Turkish drone after it came close enough to US positions supporting the Kurdish fighters to be deemed a security threat.

Blinken "highlighted the need to coordinate and deconflict our activities," State Department spokesman Matthew Miller said after the call with Fidan.