Shares in US media and entertainment companies fell on Monday after US President Donald Trump announced that he plans to impose a 100 percent tariff on films produced overseas.

Netflix Inc. and Warner Bros. Discovery Inc. fell about 3 percent while Paramount Global and Walt Disney Co. slid about 2 percent as markets opened.

In a post on Truth Social, the American leader said he was directing the Commerce Department and his trade representative to "immediately begin the process of instituting" the levy on foreign movies. "WE WANT MOVIES MADE IN AMERICA, AGAIN!" Trump continued.

The president also positioned foreign productions as a national security threat, saying other nations were using films for messaging and propaganda.

"It's not clear how such a tariff would work, nor how such movies would be valued for tariff collection purposes," reported Bloomberg News about the development. "Many films from Hollywood studios involve global production, including shooting locations in foreign countries and post-production work that can be done anywhere in the world."