BEIRUT (AP) — A cease-fire went into effect Friday after intense government attacks killed at least 37 people in an underground shelter, prompting a rebel group to call for negotiations to evacuate a new section of the besieged eastern Ghouta region near the capital Damascus, rescuers and a rebel spokesman said.

The cease-fire will mean the surrender of the second of three pockets in eastern Ghouta, where rebels have been holding up over the past years. On Thursday, hundreds streamed out of Harasta, the first pocket after a similar negotiated cease-fire and evacuation of armed fighters and civilians.

The rebel group Faylaq al-Rahman, which controls the second pocket, asked for the latest cease-fire after the intensified assault on territories it controls.

In the worst violence Thursday, a single airstrike hit the shelter in the town of Arbeen, where dozens of residents were taking refuge. Rescue teams, known as the White Helmets, said 37 people were killed. Another medical group that supports health facilities operating in the area, the Syrian American Medical Society, put the toll at 47, saying many of them were burned to death and that number was likely to rise as rescuers search through the rubble.

The strike came as government ground forces advanced into the town of Hazeh, south of Arbeen, the Britain-based Syrian Observatory for Human Rights reported.

The cease-fire went into effect after midnight Thursday, the group's spokesman Waiel Olwan said.

"We expect these negotiations to find a solution and a way out in the face of widespread suffering in eastern Ghouta," he said.

A similar deal with another rebel group, Ahrar al-Sham, led to the evacuation of hundreds of fighters and civilians from Harasta, an eastern Ghouta town in the north.

The Russian Defense Ministry said in a statement on Friday that 1,895 rebels and their family members left the town of Harasta on Thursday.

They headed to the northwestern Idlib province, one of a few remaining areas in the hands of the opposition.

Syrian state-run Al-Ikhbariya TV broadcast from the Harasta crossing area Friday, saying that 10 buses have arrived to continue the evacuation.

The evacuation deal was an effective surrender after a long siege and bombing campaign of the enclave just miles outside of Damascus. Rebels had controlled eastern Ghouta since 2012, keeping the farming area a thorn in the government's side during the years of conflict. The government imposed a siege on the area shortly after rebels controlled it, but failed to recapture eastern Ghouta.

The deal with Ahrar al-Sham in Harasta is likely to serve as a blueprint for the talks with Faylaq al-Rahman rebels.

In February, a concerted military offensive, backed by Russian airstrikes, squeezed the rebels and civilians in the area under an intense bombing campaign and tightened the siege. The U.N. estimated that nearly 400,000 people remained in the enclave before the latest offensive began.

The government assault triggered a mass movement of people trying to escape the violence in the Damascus suburbs. Some have moved deeper into the rebel-held enclave, while about 50,000 others have crossed the front lines toward government-controlled areas.

Over the last weeks, ground troops have cut the enclave into three areas, isolating them and keeping up the bombing.

On Friday, Syrian state media said more residents have left from Douma, one of the three pockets isolated by the offensive and where the bombing continues, through a crossing linking it to the capital Damascus. No cease-fire has been reached in Douma, the largest town in eastern Ghouta. Douma is controlled by the Army of Islam, the largest and most powerful rebel group in the region.

Al-Ikhbariya TV broadcast images Friday of hundreds of men, women and children streaming out on foot from the Wafideen crossing that links the rebel-controlled town of Douma to Damascus. Syrian state news agency SANA says over 4,000 left on Friday.

State media said more than 6,000 left the day before.

Syrian rescuer workers said Douma had come under intense airstrikes, counting at least 30 since late Thursday. Activists claimed incendiary bombs were used, as videos showed dark skies light up with white smoke and multiple fires raging on the ground.

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Associated Press writer Nataliya Vasilyeva in Moscow contributed to this report.