President Donald Trump is taking aim at the film industry, saying in a post on Truth Social on Sunday that he is instituting a 100% tariff on all movies produced overseas.

The president claimed that other countries’ “concerted effort” to offer incentives to draw American filmmakers and film studios internationally is a national security threat.

“Hollywood, and many other areas within the U.S.A., are being devastated. This is a concerted effort by other Nations and, therefore, a National Security threat,” Trump wrote.

The president said he’s authorizing the Department of Commerce and the United States Trade Representative to immediately begin the process of instituting a 100% tariff on “any and all Movies coming into our Country that are produced in Foreign Lands.”

While returning home to the White House on Sunday, Trump explained his post to reporters, saying the movie industry is dying, in part, because foreign countries are offering better incentives. He also blamed California Gov. Gavin Newsom.

“Hollywood is being destroyed. Now, you have a grossly incompetent governor that allowed that to happen, so I’m not just blaming other nations, but other nations, a lot of them, have stolen our movie industry,” he said.

Trump’s proposed tax on foreign movie productions leaves more questions than answers. How will the policy be implemented? What if a movie is shot, produced, or edited partially in the U.S. and in another country? And does the president even have the authority to tariff the industry?

Still, the news has Hollywood talking.

“We neither know if it’s good or bad, because, as so many Trump things are, this is a vague missive,” said Dominic Patten, the executive editor for Deadline.

Patten says the consumer would most certainly absorb the costs of any tariff on movies produced in other countries but distributed in the U.S.

“On the surface, it sounds like it could be tremendously bad, especially, perhaps, for streamers who bring in a lot of films from overseas, and of course, people doing production in places like Hungary, France, Germany, all over the world,” Patten said.

While the president’s potential tariff on the movie industry remains uncertain, state lawmakers are considering Gov. Newsom’s plan to more than double the film and television tax credit to $750 million.

If approved, it would make California more competitive with other states like New York and Georgia.

ABC News’ Fritz Farrow contributed to this report.