The Academy Award-winning director of hits such as Platoon, Born on the Fourth of July and JFK has long lionized Putin, including in a controversial 2017 documentary in which he interviewed the Russian leader.

"Putin is a stabilizing force in the Middle East... and Syria... contrary to the US," he told the Future Investment Initiative (FII) conference in the Saudi capital Riyadh.

Stone's comment comes as Russian forces filled a void in northeast Syria earlier this month left by the sudden withdrawal of American troops, leaving their Kurdish allies in the lurch.

Before Moscow launched a military intervention in Syria in 2015, rebels, jihadists and Kurdish forces held large swathes of the country.

With Russian help, the regime clawed back much of the ground it had lost in the course of the grinding war, now in its ninth year.

Read also: Oscar-winner Stone brings Putin to US television

"Mr Putin was always concerned about the terrorists. If they had gotten to Damascus... there would be a possible caliphate throughout this whole region," Stone said.

"Mr Putin doesn't have the oil interest in mind. He has the concept of keeping a balance and respecting the sovereignty of these countries."

In 2017, Stone put Putin in US living rooms by broadcasting interviews with the Russian leader.

The Putin Interviews was the product of 12 conversations between the Russian leader and Stone between July 2015 and February 2017, divided into four one-hour programs.

Putin clearly exercises fascination over Stone, who at one point tells him: "You are an excellent CEO of a company. Russia is your company."