18 dead as Syrian Kurds battle Assad forces

At least 18 people have been killed in unprecedented fighting between Kurdish forces and Syrian government troops in the northeastern city of Hasakeh, a monitoring group said Sunday.

The clashes, which erupted in the early hours of Saturday, were continuing for a second day, the Syrian Observatory for Human Rights said.

"So far, eight Kurdish People's Protection Units (YPG) fighters and security police have been killed, along with nine regime soldiers and militiamen," said Observatory director Rami Abdel Rahman.

A woman civilian was also killed in the fighting on Saturday.

The clashes broke out after Kurdish fighters detained around 10 Assad loyalists they accused of seizing part of a demilitarised zone.

Under a deal agreed last year, Kurdish forces control around 30 percent of the city's Kurdish and mixed Kurdish-Arab districts, with Assad forces controlling most of the city's majority-Arab neighbourhoods.

Certain districts are off-limits to both sides under the deal.

The two sides have fought together to keep Islamic State group out of Hasakeh, a provincial capital of some 200,000 people, but Kurdish relations with government forces are complicated.

The Assad government withdrew from most Kurdish-majority areas of Syria in 2012, focusing its forces on fighting the burgeoning Sunni Arab-led rebellion.

Since then, the Kurds have worked to build autonomous local governments in the three regions where they form the majority population.

Kurdish forces have taken over most security responsibilities in those areas.

Nusra says it shot down plane killing 35 soldiers

Meanwhile, at least 35 pro-Assad soldiers were killed overnight when an army cargo plane crashed in bad weather in the northwest of the country, the Observatory said on Sunday.

The plane crashed after hitting electricity lines in heavy fog in Idlib province, said the Observatory.

Syrian state media reported the crash without giving a death toll.

"A medium-sized cargo plane crashed last night while landing at the Abu al-Duhur military airport because of bad weather conditions and heavy fog, killing the crew on board," state news agency SANA said.

It gave no further details on the incident.

The Observatory said the plane was carrying troops as well as military equipment and ammunition.

It said pro-Assad forces were involved in heavy clashes with fighters from Al-Nusra Front in a bid to reach and recover the bodies of those killed in the crash.

On one of its Twitter accounts, Al-Nusra claimed it had shot down the plane and posted photos it said showed some of those killed in the crash, as well as the remains of the aircraft.

Militant groups have regularly shot down army planes and helicopters in the country's civil war.