Iran imposed sanctions on the United States ambassador to Yemen a day after the administration of US President Donald Trump blacklisted Tehran’s envoy to the embattled country. In a statement yesterday, Iran’s foreign ministry said Christopher Henzel was blacklisted for his “pivotal role in the occurrence of the humanitarian crisis in Yemen”. The ongoing crisis is “the biggest tragedy of the century” perpetrated by a US-led coalition that wishes to break up Yemen, it said. Henzel was designated under a law approved by the Iranian parliament in late July 2017 that is...