Russia's defense minister said on Tuesday that war-torn Syria would be ready to accept one million returning refugees, following Moscow-backed reconstruction work.

"Since 2015, when towns and villages gradually started to be freed, more than one million people have returned home," Sergei Shoigu said in comments reported by Russian news agencies.

"Now every opportunity has been created for the return of roughly one million (more) refugees," he told journalists.

"Huge infrastructure reconstruction work is ongoing, the rebuilding of transport routes and security points so that Syria can begin accepting refugees."

Russia, a long-time ally of Syria, launched a military intervention in 2015 to support the Bashar al-Assad's regime, a move that changed the course of the war.

Assad and his allies have since recovered swathes of territory and the government is turning its attention to post-conflict reconstruction, with the aid of Moscow.

The war that erupted in 2011, one of the most devastating conflicts since World War II, has displaced more than half of Syria's population, including more than five million beyond its borders.

Most of them fled to neighboring countries, particularly Turkey, Jordan and Lebanon.

Presidents Vladimir Putin and Donald Trump discussed the return of refugees at a summit in Helsinki last month.

Moscow later said it had put forward plans to Washington to cooperate on their return to Syria but details have yet to be confirmed.