WASHINGTON: The United States imposed sanctions yesterday on Iran's supreme leader Ayatollah Ali Khamenei and a string of military chiefs, tightening pressure on the country that President Donald Trump threatened with "obliteration" if it seeks war. Trump signed the punitive financial measures against in the Oval Office, calling this a "strong and proportionate response to Iran's increasingly provocative actions."

Repeating that "never can Iran have a nuclear weapon," Trump said it was now up to Tehran to negotiate. "We do not ask for conflict," he said, adding that depending on Iran's response the sanctions could end tomorrow - or it "can also be years from now." Expanding on the new measures, the Treasury said the United States will blacklist Iran's Foreign Minister Mohammad Javad Zarif and block "billions" more in Iranian assets, with eight top commanders from Iran's Revolutionary Guards already added to the list.