WASHINGTON, May 4 (Reuters) - U.S. President Donald Trump announced on Sunday a 100% tariff on movies produced outside of the United States, saying the U.S. movie industry was dying a "very fast death" due to the incentives that other countries were offering to draw American filmmakers.

"This is a concerted effort by other Nations and, therefore, a National Security threat. It is, in addition to everything else, messaging and propaganda," Trump said in a post on Truth Social.

Trump said he was authorizing the relevant U.S. government agencies such as the Department of Commerce to immediately begin the process of imposing a 100% tariff on all films produced abroad that are then sent into the United States.

Trump added: "WE WANT MOVIES MADE IN AMERICA, AGAIN!"

Commerce Secretary Howard Lutnick posting on X said: "We're on it."

Neither Lutnick nor Trump provided any details on the implementation. It was not immediately clear whether the move would target production companies, foreign or American, producing films overseas.

Film and television production in Los Angeles has fallen by nearly 40% over the last decade, according to FilmLA, a non-profit that tracks the region's production.

Meanwhile, governments around the world have offered more generous tax credits and cash rebates to lure productions, and capture a greater share of the $248 billion that Ampere Analysis predicts will be spent globally in 2025 to produce content.

The post by Trump comes after he has triggered a trade war with China, and imposed global tariffs which have roiled markets and led to fears of a U.S. recession.

Former senior Commerce official William Reinsch, a senior fellow with the Center for Strategic and International Studies, said retaliation against Trump's foreign movies tariffs would be devastating.

"The retaliation will kill our industry. We have a lot more to lose than to gain," he said, adding that it would be difficult to make a national security or national emergency case for movies.