US President Donald Trump announced a 25 percent tariff on any country doing business with Iran, ramping up pressure as a rights group estimated a crackdown on protests has killed at least 648 people.Trump, who has repeatedly threatened Iran with military intervention, said in a social media post on Monday that the new levies would “immediately” hit the Islamic republic’s trading partners who also do business with the United States.“This Order is final and conclusive,” he wrote, without specifying who they will affect.For all the latest headlines, follow our Google News channel online or via the app.Trump has been mulling his options on Iran, which has been roiled by more than two weeks of demonstrations that have defied a near-total internet blackout and lethal force.Sparked by economic grievances, the nationwide protests have grown into one of the biggest challenges yet to the theocratic system that has ruled Iran since the 1979 Islamic revolution ousted the shah.Iranian authorities