BEIRUT/DIYARBAKIR, Turkey: At least 18 people have been killed in unprecedented fighting between Kurdish forces and Syrian government troops in the northeastern city of Hassakeh, an anti-regime group said Sunday, as hundreds of civilians fled rebel-held areas near Damascus that had been blockaded for over a year.

The clashes, which erupted in the early hours of Saturday, were continuing for a second day, the Britain-based 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,” Observatory director Rami Abdel-Rahman said.

A woman civilian was also killed in the fighting Saturday.

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

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

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

The two sides have fought together to keep ISIS jihadis out of Hassakeh, a provincial capital of some 200,000 people, but Kurdish relations with government forces are complicated. The regime 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.

The army shelled three Kurdish-majority areas on the edges of Hassakeh city Saturday, and fighters from YPG clashed with Syrian forces inside the city throughout the day, the YPG said on its website.

Syrian Kurds, who say they suffered years of marginalization under Assad, had on occasion fought with the president’s loyalists in territorial disputes, but never in sustained clashes.Kurdish activists posted photos showing smoke rising from buildings and YPG fighters raising the Syrian Kurdistan flag in areas said to be taken from government forces.

Syrian officials were not available for comment and state media did not mention the clashes. A spokesman for the YPG was not available.

Damascus has promoted its ties with the Kurds, saying that it provides military support to Kurdish forces to help them battle ISIS, although the PYD denies that it cooperates with the central government.

ISIS and other hard-line groups consider Kurds heretics and have fought to take areas they control.

There were smaller scale clashes in May between Assad loyalists and Kurds in Hassakeh that were contained.

Syrian forces have evacuated nearly 4,000 people from a rebel bastion close to Damascus that has been under government siege for nearly two years, state media said Sunday. The mass evacuation from eastern Ghouta was also reported by the Observatory.

The group said former rebels granted amnesty by the government had facilitated negotiations to evacuate civilians from the area, which has suffered food and medical shortages because of the army siege.

“Army units evacuated more than 2,100 people from eastern Ghouta [Sunday],” including over 1,000 children and 350 gunmen who surrendered, Syria’s state news agency SANA reported, running photos showing cold and underfed women, children and elderly people.

It said residents of Douma, in eastern Ghouta, had “fled the crimes of terrorist organizations who use residents as human shields.”

Hundreds of women and children could be seen in footage aired by the Lebanese channel Al-Mayadeen sitting in what appeared to be a courtyard.

One of the women said rebel fighters seized men fleeing with them. “As soon as you leave, they’ll start hitting us,” she said they told the group, referring to government forces.

The woman, who did not give her name, said they had been eating stale cracked wheat and barley to survive.

Activists in those areas had said that they were mostly living without power for months, including during a snowy winter, and had only sparse food supplies.

The evacuees were taken to shelters in the Qudsaya area, northwest of Damascus, SANA added.

The agency said 2,112 people had been evacuated Sunday, and 1,687 people left the area Saturday.

A military source insisted that those leaving the area “fled to the army because of all kinds of blackmail and persecution they are being subjected to by terrorists.” The Syrian government refers to all those seeking to oust President Bashar Assad as “terrorists.”

Eastern Ghouta is a key rebel bastion on the outskirts of the capital Damascus, and has been under a tight government siege for nearly two years.