Oliver Stone has taken aim at the US government for deceiving people about the levels of surveillance that exist in the country.

The Oscar-winning director was speaking at the Toronto film festival as his new film Snowden, about the controversial NSA informant Edward Snowden, received its world premiere. The drama, starring Joseph Gordon-Levitt in the lead role, tells of the former CIA employee’s discovery that the agency had constructed a system to spy on the public.

“Americans don’t know anything about it because the government lies about it all the time,” Stone said at a press conference. “What’s going on now is pretty shocking. This story not only deals with eavesdropping but mass eavesdropping, drones and cyberwarfare. As Snowden said himself the other day, ‘It’s out of control, the world is out of control.’”

The film also features a cameo from Snowden himself, who still resides at an undisclosed location in Russia while he searches for asylum elsewhere. Stone hopes that he may return to US ground but is doubtful.

“Obama could pardon him and we hope so,” he said. “But he has vigorously prosecuted eight whistleblowers under the espionage act, which is an all-time record for an American president, and he’s been one of the most efficient managers of this surveillance world. It is the most extensive and invasive surveillance state that has ever existed and he’s built it up.”

The film-maker, known for the politically charged dramas Nixon and JFK, finds the current situation, which he likens to a George Orwell novel, to be at odds with the world that he grew up in.

“I grew up in a world where I never thought this could happen,” he said. “But from 2001 on, it’s very clear that something radical has changed. There’s more to it that meets the eye and whatever they tell you, you’ve got to look beyond.”

Gordon-Levitt met with the real Snowden in preparation for the film and believes that it’s his love of America that led him to leak classified information.

“I was interested in his patriotism,” he said. “He was doing what he did out of a sincere love for his country and the principles that the country is founded on. There are two different types of patriotism: there’s the kind when you’re allegiant to your country no matter what and you don’t ask any questions, but there’s another type which I really wanted to show in this character. The privilege of being from a free country like the US is that we are allowed to ask those questions and to hold the government accountable.”

When asked about Snowden’s future, Gordon-Levitt said: “I know he would love to come home and I hope for that.”

The film has premiered to mixed reviews at the festival, with Variety’s Owen Gleiberman calling it “the most important and galvanising political drama by an American film-maker in years” yet the Hollywood Reporter’s Stephen Farber labelled it “a lackluster opus”.