Sri Lanka, Jan. 13 -- US President Donald Trump on Monday said he had imposed a 25% tariff on goods from countries with commercial ties to Iran, a move that could put pressure on Tehran as anti-government protests enter a third week.

Trump said on social media that the tariff was "effective immediately", without offering details of what constituted "doing business" with Iran.

China is Iran's largest trading partners, followed by Iraq, the United Arab Emirates, Turkey and India.

The new tariff comes after Trump threatened to intervene militarily if Tehran killed protesters. White House spokeswoman Karoline Leavitt said on Monday that military options including air strikes were still "on the table".

"Any Country doing business with the ...