SANAA, Yemen — Forty-five members of the United Arab Emirates’ military were killed while taking part in Saudi-led operations in Yemen against Shiite rebels known as Houthis, the official news agency WAM said Friday, the largest single loss for the Gulf nation’s military to date in the war. Pro-government Yemeni security officials said the troops were killed Friday when a Houthi missile hit a weapons storage depot near their position in the province of Marib, about 75 miles east of the capital Sanaa. The seven-state Emirates federation is one of the most prominent members of the Saudi-led coalition, which aims to roll back gains by the Shiite rebels and their allies in the deeply impoverished Arabian Peninsula country. The Saudi-led and U.S.-backed coalition has been launching air strikes against the rebels since March, in an operation that aims to roll back gains by the Shiite rebels and their allies.