Turkey resumed strikes against Kurdish-held northeast Syria on Friday, targeting energy infrastructure as the death toll climbed to 15 over two days, officials in the Autonomous Administration of North East Syria (AANES) said.
Since Thursday, Turkey has carried out drone strikes against military sites and civilian facilities in the area following a weekend bombing in Ankara.
The toll in northeast Syria has risen to 15 dead including eight civilians, a statement from the US-backed, Kurdish-led Syrian Democratic Forces (SDF) said.
SDF spokesman Farhad Shami said that "since Thursday morning, we have counted more than 50 air strikes," adding that Friday's raids also targeted a gas plant near the Turkish border.
Akram Sulaiman, a local energy official, called the plant a "strategic facility" involved in feeding power to factories and hospitals in the area.
He said strikes Thursday also caused malfunctions at a power station serving neighbourhoods in Hassakeh city and its surroundings, and at another powering half the city of Qamishli further north.
Strikes also caused an outage at a station powering the nearby border city of Amuda, he added.
On Thursday, Turkish drones also targeted oil facilities and three Kurdish security forces sites, according to the Kurdish authorities.
Thick black smoke billowed from two oil sites targeted overnight, AFP correspondents said on Friday.
The bombardment comes after an attack in Ankara on Sunday wounded two security officers and was claimed by a branch of the banned Kurdistan Workers' Party (PKK), which Ankara and its Western allies view as a terrorist organisation.
Turkish Foreign Minister Hakan Fidan had warned of reprisals against Kurdish fighters in northeastern Syria, saying the assailants "came from Syria and were trained there."
The US-backed SDF, which spearheaded the fight in Syria against IS, denied the Ankara assailants had passed through the area.
Turkey views the Kurdish People's Protection Units (YPG) that dominate the SDF as an offshoot of PKK.
Pentagon spokesman Pat Ryder said US F-16 warplanes over Syria shot down a Turkish drone on Thursday, deeming it "a potential threat" after it approached "less than a half kilometre from US forces" near Hassakeh.
Since 2016, Turkey has carried out successive ground operations to expel Kurdish forces from border areas of northern Syria, and has made threats of a new incursion.