Saudi-backed Yemeni government forces staged a lightning advance on Monday to retake the coast around the Bab el-Mandeb Strait, pushing Iran-aligned Houthi fighters out of most of the territory they seized last month, the internationally recognized government said. The operation, dubbed "Dawn of Yemen," was launched Sunday by President Rashad al-Alimi, who vowed to fight "until the country is liberated from the grip of the terrorist militia."

Backed by heavy Saudi air strikes, government forces retook the towns of Dhubab, Bab and Hadeid and an airstrip at the mouth of the strait, and late Monday reached the outskirts of the port city of Mocha, with Houthi fighters retreating into the highlands, according to government sources cited by Reuters. The Saudi-led coalition said 100 fighter jets were supporting the ground forces and that it had struck hundreds of Houthi targets while securing air cover over the strait.

The Houthis rejected the claims as baseless. Their military spokesman said the rebels used ballistic and cruise missiles and drones in attacks targeting King Khalid International Airport in Riyadh, an Aramco refinery at Rabigh, Abha airport, military facilities at Khamis Mushait and other sites in Najran and Jizan — claims that could not be immediately verified. U.S. Secretary of State Marco Rubio said the Saudi-backed government had a right to defend itself.

The fighting threatens one of the world's most important oil shipping routes at a time when Gulf energy exports are already restricted by Iran's closure of the Strait of Hormuz. The Houthis also made gains of their own on Monday near Taiz, Yemen's third-largest city, reportedly cutting a mountain road and leaving government forces besieged. The UN migration agency said 184,000 people have been displaced since the war resumed.