Timothy Lenderking, the US special envoy for Yemen. Photo Courtesy of US Embassy in the United Arab Emirates
Iran, which backs Houthi rebels who have seized much of the country, last month announced a major reconciliation deal with Saudi Arabia, which led a devastating air campaign to bolster Yemen's government.
"If the Iranians want to show that they're are really turning a corner on conflict, then there won't be smuggling of weapons to the Houthis anymore in violation of UN Security Council resolutions," said Timothy Lenderking, the US special envoy for Yemen.
"We also would like to see the Iranians show support for the political process that we hope is coming," Lenderking said at the Middle East Institute in Washington.
Lenderking noted favorably that Iran welcomed the ceasefire a year ago. The truce lapsed in October, in part over Houthi demands for payments to civil servants in areas under their control, but fighting has not resumed at a significant level.
"We are urging the parties to seize this opportunity, recognizing that an agreement will require compromises from all parties," he said.
The United Nations' Yemen envoy, Hans Grundberg, on Sunday said the anniversary was a "moment of hope" although he also said there were significant risks.
Nearly a decade of war has claimed hundreds of thousands of lives, both directly and indirectly, with most of the population relying on aid to survive.
President Joe Biden took office promising a greater priority on ending the devastating conflict, after his predecessor Donald Trump's staunch backing and military support for the Saudis.
The Saudi-Iran agreement was announced by China, playing an unusually visible role in a region where the United States has long been the top power.
The United States has had no diplomatic relations with Iran since its 1979 Islamic revolution toppled the pro-Western shah.