The United States has imposed sanctions on President Bashar al-Assad and six other senior Syrian officials for the violent crackdown on political protests in the country. The sanctions freeze any assets Mr. Assad and the others have in American financial institutions, and prohibit trade with them. Besides Mr. Assad, sanctions are also imposed on Syria’s Vice president, its Prime minister, interior and Defence ministers, and the Directors of military intelligence and political security, as well as additional Syrian security and intelligence services. The US Treasury Department also imposed sanctions on the commander of Iran’s Islamic Revolutionary Guards Corps and a deputy. The senior US administration official said that Iran was providing material support to the government’s crackdown.