Saudi-backed Yemeni Government forces staged a lightning advance on Monday to retake the coast around the Bab el-Mandeb Strait up to the city of Mocha, the government said, pushing the Iran-backed Houthis out of most of the areas they seized last month.
The forces of the internationally recognised government, backed by heavy Saudi air strikes, reached the outskirts of Mocha late on Monday and Houthi fighters were retreating into the highlands, four government sources said. The Defence Ministry said the city had fallen.
The government forces had already taken key positions including an airstrip in the Dhubab district at the mouth of the strait, a vital oil route whose seizure by the Houthis last month sent shockwaves through energy markets.
Reuters could not independently verify the extent of the government gains.
The Houthis, who have controlled many of Yemen's more populous areas including the capital Sanaa since 2014, said the Saudi-backed government's claims were baseless.
While recapturing the coastal area around the strait would make it harder for the Houthis to disrupt shipping between the Mediterranean and the Indian Ocean, they could still attack vessels with drones from positions further up the coast and inland.
Meanwhile, the Houthis themselves made important advances near the city of Taiz, gaining sections of a mountain road to leave government forces there besieged, according to five military sources with the Yemeni Government. One government source denied the road had been cut.
The group also threatened to attack air traffic in Saudi airspace.
Fighting has raged along several frontlines in Yemen for weeks since a dormant civil war erupted in a spillover from the US-Iran conflict, with the Houthis seeking to control the Bab el-Mandeb Strait and firing missiles and drones at Saudi cities and infrastructure.
With Persian Gulf energy exports already restricted by Iran's closure of the Hormuz Strait, the fighting in Yemen has threatened another major oil export route, pushing up global prices and raising new risks in a region already aflame.
The renewed fighting has worsened a humanitarian crisis in Yemen; the UN migration agency said on Monday that 184,000 people had been displaced since the war resumed.
Yemen's internationally recognised president, Rashad al-Alimi, swore on Sunday to fight, "until the country is liberated from the grip of the terrorist militia".
Saudi Arabia, which arms and trains the Yemeni Government forces, is backing the campaign with air power and has sought logistical help from allies to push back the Houthis, restore free traffic in the Red Sea, and end the group's attacks on its territory.
Riyadh said on Monday it had attacked hundreds of targets to provide air cover for the Bab el-Mandeb Strait and Yemeni ground forces. The Yemeni Government said it had launched attacks on several fronts including in Sanaa province.
The Houthi-run health ministry said two people had been killed and seven wounded in strikes on the province's Sanhan and Sa'wan districts.
While the war has raged on several fronts, the heaviest fighting has been in the southwest, both in the coastal area near the strait and in the hills around Taiz.
Last week, Houthi attacks damaged a culvert on the Taiz-Aden road, making it impassable.
On Sunday night, the group's fighters made new advances into the town of al-Turbah, atop a promontory on the road, five government military sources said, though another government source denied this.
A Houthi-run news agency on Monday cited a military source as saying the group had driven government forces from the al-Mawasit district of Taiz province, reaching the home of Alimi, head of Yemen's interim presidential council.
The advances left Taiz, Yemen's third city with a population of over half a million and a garrison of thousands of government fighters, surrounded by Houthi forces, the government military sources said.
Taiz, nestled among Yemen's southern highlands, has been on the frontlines since early in the civil war, often under Houthi shell and sniper fire.
In al-Mudhaffar area, just outside Taiz but within the area besieged by the Houthis, a long queue formed outside a petrol station on Monday as people waited for fuel and cooking gas canisters.
"This is the daily state in Taiz," said one man queuing, Shehab Hazaa.
The year after the Houthis seized Sanaa in 2014, a Saudi-led coalition mounted an air campaign aimed at restoring the government and ousting the Iran-backed group.
The fighting ground to a bloody stalemate and triggered one of the world's worst humanitarian crises in what was already the poorest Arab state, until a ceasefire was agreed in 2022 that held until this summer.
(Reporting by Timour Azhari in Riyadh, Mohammed Ghobari, Menna Alaa el-Din and Jana Choukeir; Writing by Angus McDowall; Editing by Gareth Jones and Kevin Liffey)