Washington DC - President Donald Trump on Monday announced a 25% tariff on any country trading with Iran, ramping up pressure on Tehran over its violent crackdown on a wave of protests.

"Effective immediately, any Country doing business with the Islamic Republic of Iran will pay a Tariff of 25% on any and all business being done with the United States of America. This Order is final and conclusive," Trump said on Truth Social.

Iran's main trading partners are China, Turkey, the United Arab Emirates, and Iraq, according to the economic database Trading Economics.

The tariffs announcement comes as Trump mulls possible military action against Iran over the protests. Rights groups have reported a growing death toll.

"One thing President Trump is very good at is always keeping all of his options on the table," White House Press Secretary Karoline Leavitt said earlier Monday.

"And air strikes would be one of the many, many options that are on the table for the commander in chief."

But she said Iran also had a diplomatic channel open to Trump's special envoy Steve Witkoff, adding that Iran was taking a "far different tone" in private than it was in its public statements.