US President Donald Trump has imposed a 25% tariff on any country that does business with Iran.

On Monday, Trump said the levy was “effective immediately” and called the decision “final and conclusive” in a post on his Truth Social platform.

“Any country doing business with the Islamic Republic of Iran will pay a tariff of 25 percent on any and all business being done with the United States of America,” he wrote.

Trump did not elaborate on how the measure would be implemented or what level of commercial relations would constitute “doing business” with Iran.

This announcement comes amid huge anti-government protests in Iran, which began on December 28 when Tehran shopkeepers denounced another significant drop in the rial’s value against the US dollar.

The demonstrations spread to neighboring cities, with demonstrators expressing larger concerns about economic hardship and political problems.

According to the Iranian Human Rights Activists News Agency,based in the US,  protests took place in at least 186 cities and villages across all Iran’s regions.

According to human rights organizations, hundreds of protestors have been murdered and thousands injured as a result of the security forces’ violent crackdown.

Iran Human Rights, a Norwegian organization, reported that at least 648 protesters have been murdered since the rallies began, with thousands more injured.

“They fired directly into lines of protesters, and people fell where they stood,” an eyewitness told BBC.

Iranian authorities ordered a digital blackout, cutting off millions of people’s internet connection and making independent verification of events difficult.

Iran’s economy has been strained due to government mismanagement, corruption, and long-standing US sanctions related to its nuclear programme.

Over the last year, the rial dropped to its lowest point ever, while inflation has skyrocketed, driving up the cost of basic necessities like food.

Food accounts for around one-third of Iran’s imports, and more trade restrictions could exacerbate shortages and drive up prices for regular Iranians.

Trump had previously warned of the possibility of US intervention, stating that Washington was studying “very strong options” in response to the violence.

He has also stated that the US is willing to “rescue” Iranian demonstrators if the government continues to use force against them.