WASHINGTON: The United States on Tuesday imposed sanctions on Iran's envoy to Yemen's Huthi rebels, stepping up pressure as President Donald Trump considers a controversial designation of the insurgents as terrorists. The Treasury Department designated under counterterrorism laws Hasan Irlu, described by Iran as its ambassador to Yemen, where the Huthis control broad swathes of territory including the capital Sanaa.

"Iran's support for the Huthis fuels the conflict in Yemen and exacerbates the country's instability," Secretary of State Mike Pompeo said in a statement. Through Irlu's presence in Yemen, the Iranian Revolutionary Guards elite Qods Force "is signaling its intent to increase support to the Huthis and further complicate international efforts to reach a negotiated settlement to the conflict," Pompeo said.

US officials say Iran has provided military support to the Huthis, with which it shares religious ties, although analysts debate the extent of involvement, with some seeing Tehran primarily as interested in bogging down its regional rival Saudi Arabia. Yemen has been the scene of a humanitarian catastrophe as a Saudi-led coalition targets the Huthis, with a heavy toll on civilians including destruction of schools and hospitals.