Backed by Turkish tanks and reports of airstrikes, Turkey-allied Syrian rebels clashed with Kurdish-led forces in northeastern Syria in a new escalation that further complicates the already protracted Syrian conflict.

Turkey's military didn't specify what the airstrikes hit, saying only that "terror groups" were targeted south of the village of Jarablus, where the clashes later ensued. A Kurdish-affiliated group said their forces were the target and called the attack an "unprecedented and dangerous escalation." If confirmed, it would be the first Turkish airstrikes against Kurdish allied forces on Syrian soil.

Late Saturday night, Turkey's official news agency reported that one Turkish solider had been killed and three wounded by what it said was a Kurdish rocket attack in Jarablus, near where the fighting has raged. It is the first reported Turkish fatality in Syria.

The new escalation highlights concerns that Turkey's incursion into Syria this week could lead to an all-out confrontation between Ankara and Syrian Kurds, both American allies, and hinder the war against the Islamic State (ISIS) group by diverting resources.

Sherwan Darwish, a spokesman for Kurdish-led forces in the village of Manbij, said on Twitter Saturday night: "While our forces fighting #IS Some #Turkey backed militias r attacking our positions & hampering our & Intl Coalition's fight against terror."

The clashes underscore Ankara's determination to push back Kurdish forces from along its borders, and curb their ambitions to form a contiguous entity in northern Syria. Kurdish groups have already declared a semi-autonomous administration in Syria and control most of the border area.

Jarablus, and Manbij to the south liberated from ISIS fighters by Kurdish-led forces earlier this month, are essential to connecting the western and eastern semi-autonomous Kurdish areas in Syria.

Turkish officials said they will continue their offensive in Syria until there is no longer any "terror" threat to Turkey from its war-torn neighbor. Ankara backed Syrian rebels to gain control of Jarablus last week. They are now pushing their way south.

On Saturday, the Syrian rebels said they have seized a number of villages south of Jarablus from ISIS militants and Kurdish forces. Clashes were fiercest with the Kurdish-allied forces over the village of Amarneh, five miles south of Jarablus.

The media office of the Turkish-backed Nour el-din el-Zinki rebel group said the Syrian rebels were backed by Turkish tanks. A news report on ANHA, the news agency for the semi-autonomous Kurdish areas, said local fighters destroyed a Turkish tank and killed a number of fighters in an attack by the Turkish military and allied groups on Amnarneh.

There was no immediate comment from Turkish officials.

The clashes were preceded by Turkish airstrikes against bases of Kurdish-affiliated forces and residential areas at Amarneh. The Jarablus Military Council, affiliated with the U.S-backed Kurdish-led Syria Democratic Forces, said the Turkish airstrikes marked an "unprecedented and dangerous escalation" that "endangers the future of the region."

It vowed to stand its ground. Other groups which are part of the SDF vowed to support them, calling on the U.S-led coalition to explain the Turkish attacks on allied forces.

Turkey's state news agency, citing military sources, said the Turkish Military Joint Special Task Forces and coalition airplanes targeted an ammunition depot and a barrack and outpost used as command centers by "terror groups" south of Jarablus Saturday morning. The Anadolu Agency did not say which group or village was targeted.

Turkey has long suspected the Syrian Kurdish People's Protection Units, or YPG, of being linked to Kurdish insurgents in its own southeast, which it labels as a terror group. It has demanded the YPG, which makes up the bulk of the SDF and has been one of the most effective U.S. ally in the fight against ISIS, withdraw to the east bank of the Euphrates River.

The U.S. supported Turkey's call for the Kurdish forces to move back, and Kurdish officials said they withdrew the YPG forces from Manbij. But following the Turkish offensive, local forces with Kurdish fighters and backed by YPG advisers pushed their way north of Manbij, in a rush for control of Jarablus.

Meanwhile, the U.N. special envoy to Syria, Staffan de Mistura, appealed to the opposition to approve plans to deliver aid to rebel-held eastern Aleppo and government-held Aleppo through a government-controlled route north of Aleppo during a 48-hour humanitarian pause.

Aleppo has been caught in a bloody circle of violence, with rebels and government forces each promising to unite the divided city. The U.N. said it has pre-positioned aid ready for delivery into Aleppo, to reach 80,000 people on the rebel side and some on the government side. But the opposition, whose fighters have opened another route in the south, were wary of the use of the government-controlled route.

"People are suffering and need assistance. Time is of the essence. All must put the civilian population of Aleppo first and exert their influence now," de Mistura said in a statement, urging an approval by Sunday.

But violence raged. Suspected government helicopters dropped two barrel bombs on a wake held for children killed a few days earlier, killing at least 15, according to the Britain-based Syrian Observatory for Human Rights.

The Aleppo Media Center, an activist group in the city, and volunteers on the scene put the death toll higher at 24.

Mohammed Khandakani, a hospital volunteer, said one of the injured told him a barrel bomb was dropped in the Bab al-Nairab neighborhood as people paid their condolences for children killed Thursday in an airstrike that left 11 children dead in the same neighborhood. Minutes later, Khandakani said another barrel bomb was dropped, injuring an ambulance driver, and hampering rescue efforts.

The Syrian government and its Russian ally are the only ones operating helicopters over Aleppo. The government denies it uses barrel bombs.

Elsewhere, the Syrian government said it now has full control of the Damascus suburb of Daraya, following the completion of a forced evacuation deal struck with the government that emptied the area of its remaining rebels and residents and ended a four-year siege and grueling bombing campaign.

The declaration comes a day after the evacuation of nearly 5,000 residents and fighters from the suburb began. The deal followed an extensive government campaign of aerial bombing and shelling of Daraya, the last bastion against President Bashar Assad in the western Ghouta region, southwest of Damascus.

Some 700 gunmen and 4,000 civilians were evacuated. The gunmen and their families headed to the northern rebel-controlled Idlib province. Other civilians were escorted to shelters in government-controlled suburbs of Damascus.