NEW YORK: Yemeni staff employed by the US embassy in Sanaa are still being harassed and detained by the Houthis, the American ambassador to the UN told the Security Council on Tuesday. Linda Thomas-Greenfield added that the militia also continues to ignore repeated calls by the international community to end its offensive in Marib, and has intensified its cross-border attacks on targets in Saudi Arabia. These “provocative and dangerous actions (underscore) the need for Iran to end its lethal support to the Houthis, which contravenes this body’s resolutions and enables the Houthis’ reckless attacks,” she said. Thomas-Greenfield was speaking at a regular Security Council meeting on the situation in Yemen, during which members were briefed by Hans Grundberg, the UN’s special envoy to the country. He expressed alarm about the ongoing Marib offensive, and violence he said has “escalated considerably” with the “risk that this could open a new chapter of the Yemen war that is even more fragmented and bloody.” The offensive is endangering thousands of people, Thomas-Greenfield said, and could cause the displacement of half a million civilians. “The Houthis must stop this offensive immediately,” she reiterated. On Dec. 9, a Houthi missile hit a camp for the internally displaced managed by the International Organization for Migration. Five children were among the injured. “This is unacceptable,” said Thomas-Greenfield. “We condemn in the strongest terms this and similar, all-too-frequent attacks against civilians.” The American envoy also condemned “the intensification of Houthi cross-border attacks on Saudi Arabia in recent months, including three ballistic missiles launched at Riyadh just last week.” She added: “The Houthis have conducted well over 350 such attacks this year — a staggering number and a shocking increase from last year’s total. “Each of these Houthi attacks, on its own, is unacceptable. Together, they send a chilling and unmistakable signal about Houthi unwillingness to participate in a peaceful political process or in a future government that upholds the rule of law.” Turning to the seizure of the US embassy in Sanaa, Thomas-Greenfield called on the Houthis to release unharmed all remaining workers from the site who are still detained, immediately vacate the compound, return seized property and “cease their threats against their own fellow citizens, simply for being employed by us.” Operations ceased at the embassy in 2015 and American staff were withdrawn but Yemeni workers remained, providing security and caretaker services. Dozens of them were detained when the Houthis breached the compound in mid-November. Thomas-Greenfield also issued another warning about the danger posed by the Safer, an oil tanker that has been moored in the Red Sea off the coast of Yemen since 2015 and is estimated to contain about 1.14 million barrels of oil. Its condition has deteriorated significantly and it “remains an environmental, humanitarian, and economic threat of vast proportions,” said Thomas-Greenfield. “The Houthis bear responsibility for this situation, and the United States supports discussion of any solution that can safely and urgently address it,” she added. Calling on all parties to engage with Grundberg in his efforts to create a framework for an inclusive political process in Yemen, she warned that if the conflict continues, “Yemen’s economy will deteriorate further, and with it the livelihoods of millions of Yemenis. Lives will continue to be endangered, and generations of Yemenis will bear its scars.” However, she added: “While the Houthis continue their escalatory actions, we welcome the efforts of other parties to improve conditions in Yemen, including the UN initiative to scale up its approach for addressing the drivers of food insecurity throughout Yemen.” Thomas-Greenfield said that the US, like the UK, is “encouraged” by the appointment on Dec. 6 of a new governor of the Central Bank of Yemen, along with a new chairman of the board and other new board members. “We hope these appointments serve as a step forward in addressing the economic instability that is deepening humanitarian suffering and will push forward needed reforms,” she added. “True progress cannot be sustained, however, without additional resources. We hope countries can seize this moment to support Yemen’s economy and bring urgently needed relief to its people. The special envoy’s strong appeal for action has been heard loudly and clearly by this Council.” She concluded: “In the face of Houthi provocations, harassment and violence against their own people, I want the Houthis to know that the United States will never give up on the people of Yemen.”