A day earlier, the Russian military police started entering Douma and the Syrian police entered that area on Saturday.
Eastern Ghouta has "been totally cleansed of terrorism", the spokesman said in a statement broadcast on state television.
Douma is the main town in what at the start of the year was a sprawling semi-rural area just east of Damascus, home to nearly 400,000 inhabitants.
The extreme bombardment killed some 1,700 civilians in line with the Syrian Observatory for Human Rights, a Britain-based monitor, and pulverised the realm, decreasing many neighbourhoods to rubble.
Douma and the sprawling eastern Ghouta region near the capital, Damascus, had been under rebel control since 2012 and was a thorn in the side of President Bashar Assad's government for years.
The United States, France and Britain responded yesterday with pre-dawn strikes on alleged regime chemical weapons sites.
The rebels surrendered Douma after a suspected chemical weapons attack last weekend.
Assad had made the reconquest of Eastern Ghouta a strategic goal.
The group has slammed the Western strikes as inadequate, as Assad maintains his grip on the war-ravaged nation.
Protests break out across the country over Kathua, Unnao rape cases
According to the reports, the girl had taken some cows out to graze and was searching for a missing cow when she was abducted.
The last convoy of buses transporting members of the Islamist group Jaish al-Islam and their relatives left Douma yesterday.
The Syrian government strongly denied the allegation, calling for the Organization for the Prohibition of Chemical Weapons (OPCW) to send a fact-finding mission for investigations.
The 2-month assault on Jap Ghouta sparked a global outcry, with the pinnacle of the United Nations describing the circumstances endured by civilians there as "hell on Earth".
Since the beginning of the humanitarian operation in Eastern Ghouta, the Russian reconciliation center played a decisive role in organizing evacuation of 67,680 militants and their families, according to the general.
"Following a number of concentrated and powerful military operations in the past week, units from our courageous armed forces and its allies managed to cleanse Eastern Ghouta in all its neighborhoods and (surrounding) villages, from the armed terrorist organizations after driving out all terrorists from the city of Douma, the final base for terrorists in Eastern Ghouta", said a statement released by the military late on Saturday.
The Syrian Army said a clean-up operation was underway in the battered enclave.
It added that the army is preparing eastern Ghouta for tens of thousands who were displaced over the past two months during a crushing government offensive to retake the area.
Numerous Jap Ghouta residents had been bussed to the northern province of Idlib, which is basically exterior authorities management and hosts a number of jihadist and different insurgent teams.