Russia-backed regime forces have recaptured the vast majority of the enclave through the combination of a deadly air and ground assault and evacuation deals.
Syrian regime forces said on Saturday they have regained most of the towns and villages in eastern Ghouta and were pressing their military operations in the last opposition-held bastion of Douma.
In a televised statement, the Syrian regime forces spokesman said the weeks-long military campaign had now brought security to the Syrian capital, Damascus, and also secured its main links to other parts of the country, stretching north and all the way to the Iraqi border to the east.
A last group of opposition fighters and families had earlier left the main towns of Jobar, Zamalka, Arbeen and Ain Tarma after the fall of other towns, leaving only the city of Douma still in the hands of opposition groups.
Footage on state television showed top regime commanders entering by the same route opposition fighters had used to leave.
Tens of thousands of people have now evacuated once-bustling towns in the suburbs east of the capital, which had nearly 2 million people before the start of the conflict and were major commercial and industrial hubs.
The regime command said military operations were continuing in the outskirts of the city of Douma, controlled by the Jaish al Islam group, the last patch of eastern Ghouta still held by opposition groups.
Douma's fall would seal the opposition's worst defeat since 2016, driving them from their last big stronghold near the capital, and would also carry potent symbolism. The town was the main centre of street protests in the Damascus suburbs against regime leader Bashar al Assad's rule that ignited the conflict seven years ago.
Regime forces said hundreds of fighters had been killed in the ferocious offensive. The opposition says a relentless air campaign was waged in which troops used napalm, chlorine and incendiary bombs to demoralize rebels by targeting civilian areas.
Opposition fighters say the indiscriminate bombing forced them to capitulate and agree to surrender deals that force them either to make peace or leave to rebel-held areas after weeks of bombing and sieges that prevented food from reaching the enclaves.
The Syrian regime has repeatedly said regaining control over opposition-held suburbs would stop rocket attacks on the capital.
They deny that many civilians were killed in bombardments that rescuers and residents say reduced whole neighbourhoods to rubble in densely populated areas where at least 350,000 people lived.
Defence analysts say a major goal of the campaign was to complete a security belt around the capital, where for years opposition groups dug into an elaborate network of tunnels and well-fortified positions had resisted countless offensives to seize the enclave.
Trapped in Douma
Douma is surrounded by regime forces, many of whom were elite forces from the Republican Guards and special army units, who have been amassing troops in recent days and threatening to storm the city if fighters do not agree to leave.
Tens of thousands of civilians remain in Douma, which is the largest urban centre in the enclave, facing worsening humanitarian conditions.
Opposition fighters there deny they are negotiating an evacuation deal and say talks with the Russian military are aimed at finding a solution that would allow them to stay in the city under Moscow's protection.
Negotiators, however, reached a deal with the Russian military late on Saturday to evacuate the wounded in the city to insurgent-held areas in northwestern Syria, local sources said.
It was not clear if the step would pave the way towards a broader deal to evacuate fighters in an arrangement similar to one that was brokered by the other main rival opposition group, Failaq al Rahman, with Moscow that has allowed most of its fighters to leave their former areas of control.
The Syrian army offers defeated rebels either the option of making peace and switching sides or surrendering their weapons and leaving for regime-controlled areas.
'Beating heart of the rebellion'
With the offensive on eastern Ghouta, Assad has sought to secure his capital Damascus, which was within mortar range of the rebel enclave.
Last week, a rebel rocket attack on the capital killed 44 civilians.
Assad's forces retaking eastern Ghouta would be a considerable victory in Syria's seven-year war, which has killed more than 350,000 people and displaced millions.
Syria's civil war started in 2011 with the brutal repression of anti-government protests.
Eastern Ghouta is the "beating heart of the rebellion near Assad's capital," said analyst Nick Heras, a fellow at the Center for a New American Security.
"When Assad stops that heart from beating, he eliminates the greatest threat to his rule in Damascus."