ADEN: Yemeni forces backed by the United Arab Emirates have joined coalition troops fighting the Houthi movement around the central city of Marib in a renewed push to secure the prize of an energy-producing region. The battle for Marib, where the Iran-aligned Houthis had advanced on most districts barring the main city and nearby hydrocarbon sites, dashed hopes for any imminent truce that the United Nations and the United States have struggled to engineer.

U.N. special envoy for Yemen, Hans Grundberg, told the Security Council on Wednesday that both sides are “doubling down on military options” and warned of devastating implications for civilians and immediate peace prospects.

The nearly seven-year-old conflict, largely seen as a proxy war between Saudi Arabia and Iran, has killed tens of thousands of people, displaced millions and pushed Yemen to the verge of famine as the economy collapsed.

Over the past month, fighting in al-Jawf in the north, Marib in central Yemen and Shabwa in the south has displaced more than 15,000 people, according to the United Nations.

“People are pessimistic and do not know where the country is heading,” Abdullah al-Nisi, an engineer in Shabwa, told Reuters.

The Saudi-led coalition this week announced a new operation aimed at turning the tide after newly deployed UAE-backed Giants Brigade forces, supported by air strikes, expelled Houthi forces from oil-producing Shabwa, reopening access to Marib.