VENICE - Hollywood star Natalie Portman called school shootings America's "civil war" Wednesday, comparing the psychological torment they cause to the threat of terror attacks.

The Oscar-winning actress drew the parallel before the premiere of her new film about a traumatized pop diva, "Vox Lux", which opens with a Columbine-style massacre.

"I have been interested in the questions around the psychology of what violence does to individuals and in mass psychology for some time, coming from a place where people have encountered violence for so long," said the Israeli-born star, best known for "Black Swan".

"Unfortunately it is a phenomenon we now experience regularly in the United States with the school shootings.

"As (the film's director) Brady (Corbet) has put to me before, it is a kind of civil war and terror that we have in the US," she told reporters.

The regular mass killings were having a "psychological impact on every kid going to school every day and every parent dropping their kids off," said added.

"Small acts of violence can cause widespread torment."

Portman, 37, plays a singer who is badly wounded in a bloodbath at her school but builds a pop career after she sings at a memorial for her classmates.

The movie's director Corbet, who was a schoolboy in Colorado at the time of the Columbine killings, confessed that the massacre "marked me psychologically. I was living there when it happened. It was close to home."

Corbet, who is best known as an actor - starring in "Thunderbirds" and Michael Haneke's "Funny Games" - was editing his award-winning directorial debut, "The Childhood of a Leader", in Paris when the city was hit by a wave of terror attacks in 2015.

"I had a five-month-old (child) at that point, and me and my wife were shaken by it. One restaurant that got shot up was a place we went a few times a week, it was a narrow miss. We were haunted by it," he said.

Corbet described his story as a "poetic rumination of what we have all been through... We live in an age of anxiety. We are having more sleepless nights than ever."

He said the film, with its anti-heroine star -- played by British actress Raffey Cassidy in her younger years and Portman when she becomes a Madonna-like diva -- was meant as a salve, "something we could come together over".

"When I think about what will define the early 21st century, especially as an American, it's Columbine, 9/11 and the global terror threat that has permeated every place I have lived. I wanted to look at what we've all been through in the last 20 years," he told Screen magazine earlier. - AFP