The US is imposing sanctions on two Houthi commanders leading the fighting in Yemen’s Marib province, Washington’s special envoy to the country said on Thursday. It comes as the Houthi militias that control a large part of the country continue to block efforts by the UN and the US to resolve the conflict, Tim Lenderking added, and are endangering the lives of refugees. The humanitarian situation in the country continues to deteriorate, he said, with more than a million internally displaced persons living in dire conditions, especially after recent fighting in the Marib. The sanctions target Muhammad Abd Al-Karim Al-Ghamari, who is head of general staff of the militias’ forces and leads the Marib offensive, and Yusuf Al-Madani, a leader of forces assigned to the advance in the province. The Houthis are still failing to cooperate with the UN and US on a number of issues, Lenderking said. In particular they are not engaging with efforts to help internally displaced refugees and are “putting their lives in danger.” They have also failed to respond positively to peace overtures aimed at ending the conflict and have “backtracked” on commitments they made, he said, even as Washington made a number of concessions that benefited them. Lenderking pointed out that the Biden administration agreed in February to revoke the designation of the Houthis as a foreign terrorist organization, overturning a Trump-era ruling, in return for assurances that humanitarian aid would be allowed to reach the people of Yemen. He said that the US has given more than $3 billion to Yemen since the conflict began, in the form of economic and humanitarian aid, and the administration is keen to alleviate the suffering of the Yemeni people by ensuring that vital aid can reach them. “It is a fundamental pillar of the United States that all economic arteries, all ports, all airports in Yemen should be open for commerce and for the access for vital humanitarian supplies,” he added. US authorities are disappointed that the Houthis declined to meet with Martin Griffiths, the UN’s special envoy to Yemen, during his recent visit to Oman, Lenderking said. Washington remains strongly committed to ending the Yemen conflict, he added, and to working to achieve this with authorities in Saudi Arabia. He said he recently visited the Kingdom to meet Crown Prince Mohammed bin Salman. The envoy added that he had traveled to the region with Griffiths and US Senator Chris Murphy, “which I think really showed the alignment between the branches of the US government and the United Nations.” The conflict in Yemen began in the aftermath of the so-called Arab Spring of 2011, when the Yemeni people sought to remove from power President Ali Abdullah Saleh. He resigned in February 2012, handing power to his deputy, Abed Rabbo Mansour Hadi. But Houthi rebels, who had fought the central government for years, gained control of the capital, Sanaa, in early 2015 as the country descended into civil war, creating a humanitarian crisis on a massive scale. Saudi Arabia, the UAE and other nations in the region formed an “Arab Coalition” in 2015 to fight the rebels and help restore to power the nation’s government.