Yemen's internationally recognized government pressed world leaders anew Thursday for help defeating the Iran-backed Houthi rebels, saying that their new perch along one of the world's busiest waterways presents an international economic risk.

The Houthis — who have controlled Yemen's capital, Sanaa, and much of the country's north for over a decade — stormed down Yemen's coast this month and seized the crucial port city of Mokha and key Red Sea islands. That gives them better surveillance of ships passing through the Bab el-Mandeb Strait, at the sea's southern end. About 12% of the world's trade usually passes through the waterway.