BEIRUT: Three years ago, the Army of Islam, one of Syria’s most powerful armed opposition groups, held a massive military parade that included thousands of opposition fighters marching in formation and a striking display of tanks and armored vehicles at the doors of the Syrian capital. The parade, held in the town of Douma in the spring of 2015, demonstrated the group’s growing clout in the eastern Ghouta suburbs, which for years were seen as a potential launch pad for a ground attack on Damascus, seat of President Bashar Assad’s power. The Army of Islam now stands alone in eastern Ghouta, its fighters facing a stark choice: Surrender or die. Haitham Bakkar, a Douma-based opposition activist, said the situation in Douma is very tense because it is unclear what will happen next. He said it was a question of existence for the Army of Islam fighters, most of whom are from Douma. “If the Army of Islam goes to northern Syria it will be its end,” he said. Douma, on the northeastern edge of Damascus, is the last rebel holdout in the eastern Ghouta region after thousands of fighters from the Ahrar Al-Sham and Faylaq Al-Rahman groups ceded their towns to government control under a deal brokered by Russia, a key ally of Assad. For days, their fighters have been exiting from the southernmost pockets of eastern Ghouta, leaving in a fleet of buses, including the lime-green municipal buses that have come to symbolize defeat for the Syrian opposition as the government takes back control of cities around the country. The Ghouta fighters join tens of thousands of rebels from other areas of Syria, including Aleppo and Homs, who were driven out in the past few years following similar deals with the government that granted them safe passage to the north in return for abandoning the rebellion. With the help of Russian airstrikes, the army has waged a crushing air and ground offensive to recapture eastern Ghouta, killing more than 1,600 people since Feb. 18, according to the Syrian Observatory for Human Rights. Five weeks later, the eastern Ghouta region, once a cluster of around 15 rebel-held towns spread east of Damascus, has been overtaken by government forces, except for Douma, where the Army of Islam is headquartered. Rebels who have left eastern Ghouta so far have all gone to Idlib, an insurgent-held region dominated by Al-Qaeda-affiliated fighters near the Turkish border, where they either have a presence or good relations with Turkey. By contrast, the Army of Islam, called Jaysh Al-Islam in Arabic, is home-grown and has no other strongholds in the country. “Jaysh Al-Islam is a very local phenomenon, emerging from the specific social fabric and Salafi school of thought of the Damascus countryside,” said Faysal Itani, a senior fellow at the Washington-based Atlantic Council. “More precisely, Jaysh Al-Islam is a creature of Douma, and I don’t know how it would survive outside it,” especially in Idlib, where there is rebel rivalry, he said. It is a resounding defeat for the powerful group that once briefly overran parts of Damascus and showered the capital with mortar shells. Thousands of Army of Islam fighters — some estimates say around 10,000 — are now encircled in Douma, a densely populated town with a huge number of civilians who are terrified of what they see as a looming army offensive if the rebels don’t exit. One resident said there are currently about 150,000 civilians in Douma, many of them internally displaced from other towns in eastern Ghouta, some of them staying out in the open or in destroyed buildings. This civilian pressure is weighing on the group as it negotiates with the government and its Russian backers. Several opposition activists have said that the Russians have given the Army of Islam 48 hours as of early Tuesday to leave Douma for northern Syria or face an all-out offensive. But the group’s military spokesman, Hamza Bayraqdar, denied the reports and said Army of Islam fighters would never leave, describing the evacuations to the north as forced displacement. “We are negotiating to stay, not to depart,” he told Al-Arabiya TV on Tuesday. “The people who will leave eastern Ghouta will never dream of returning to their homes.” The group has no good choices. Going to Idlib would put its fighters in an area dominated by Al-Qaeda, against whom it has fought pitched battles in the past. The Britain-based Observatory reported this week that the Russians rejected a request by some Army of Islam members to head to the southern province of Daraa. The rebels, meanwhile, are bitterly blaming each other for their defeat in Ghouta. After Faylaq Al-Rahman began withdrawing from eastern Ghouta, Army of Islam members blasted their former allies, accusing them of helping government forces by drying out artificial swamps set up by insurgents to slow down the army’s offensive. “We had defensive plans prepared, but regrettably Faylaq Al-Rahman cut the water that was brought from Barada River,” Bayraqdar said. “This sped up the regime’s advance.” Asked about the charges, Faylaq Al-Rahman spokesman Wael Olwan said: “I don’t want to respond because we are trying to avoid their irresponsible statements.” Olwan told The Associated Press that it is still not clear whether Faylaq Al-Rahman’s members will end up in Idlib or in areas controlled by Turkish troops. “I still don’t know what our role will be,” he said.