The district is besieged by Syrian government forces.
Mohammad Adel, an antigovernment activist in Douma, said H.T.S. had endangered people in Eastern Ghouta, declared Muslims who disagree with the group nonbelievers, and soured residents on the other rebel groups.
In around two weeks, the Syrian army has retaken almost all the farmland in the enclave east of Damascus under cover of near-ceaseless shelling and air strikes, leaving only a dense sprawl of towns - about half the territory - still under insurgent control.
"The regime has cut Ghouta into three parts by cutting the main roads linking them", said the Observatory's chief Rami Abdurrahman. The civilian death toll has since risen to around 900. More than 4,350 have been wounded.
Tens of thousands of people have fled further into the enclave in the face of the warfare, a United Nations official said on Thursday, and residents of Douma said shelters were crowded with the new arrivals.
"The bombing is so intense".
Harasta was one of the earliest rebel-held cities in Syria and was reported under rebel control by early 2012. With the help of Russia, President Bashar al-Assad has employed an offensive that includes relentless air strikes and tight sieges to pressure rebels into "evacuation deals".
The Syrian government has reportedly captured the central town of Misraba, and advanced onwards into surrounding farmland.
One elderly man broke down into tears as he relayed how his family had fled to Douma under fierce bombardment.
An aid convoy crossed into the embattled rebel-held suburbs of Damascus Friday, delivering desperately needed aid despite heavy fighting that broke out "extremely close" to the convoy and renewed airstrikes by the Syrian government. Another aid convoy is scheduled to enter eastern Ghouta on Thursday, but Laerke said security measures must be guaranteed for this to happen.
Hamza Hassan, a surgeon working at one of the hospitals in eastern Ghouta, said that staff was overwhelmed with chlorine odour and that he treated 29 children with breathing problems.
On Friday, 13 HTS members and their relatives were bussed out of the enclave. The TV station said authorities will move the almost 60 people to a safe location where they will be given shelter and food.
The Syrian government does not cooperate with the UN Human Rights Council (UNHRC) believing that the body is propagating the anti-Syrian policy of western countries, Syrian Deputy Foreign Minister Faisal Mekdad said.
That paved the way for Syria's government to announce the full recapture of Aleppo - the largest defeat to date for the fractured opposition movement. The advance is seen as a significant development in the bloody conflict in the region.
Russian Federation has intervened on Assad's behalf while Turkey has backed rebels against his regime, rival militants and Kurdish forces.
In January, Turkey began an offensive to oust the Kurdish YPG militia from the Afrin region in northern Syria, near the Turkish border.