They said warplanes flew between 15 and 20 sorties against groups of Houthi fighters and arms depots in the al-Dhalea provincial capital, Dhalea, and the nearby city of Qa’ataba, between dawn and 0900 local time (02:00 a.m. EDT), setting off a chain of explosions.
Dhalea residents said sounds of explosions could be heard for two hours after the strikes.
Saudi-led warplanes also struck the area around the presidential compound in Sanaa for a second day, while heavy street fighting was under way in the strategically important city of Taiz in central Yemen, according to residents and the International Committee of the Red Cross.
There were no immediate reports on the extent of casualties.
A coalition of Arab countries led by Saudi Arabia, rattled by what they saw as expanding Iranian influence in the Arabian Peninsula, has carried out nearly five weeks of air strikes on Houthi fighters and loyalists of former President Ali Abdullah Salah who have together seized large parts of Yemen.
Fighting has killed more than 1,000 people, including an estimated 551 civilians since the bombings started on March 26, the United Nations said on Friday. Its children’s agency UNICEF said at least 115 children were among the dead.
Saudi Arabia, the world’s top oil exporter and arch Sunni Muslim regional rival of Shi’ite Muslim Iran, says it was concerned over its own security after Houthi forces began advancing across Yemen, on its southern border, in September, when the Shi’ite militia captured the capital.
The Houthis allege President Abd-Rabbu Mansour Hadi fostered Islamist militants linked to al Qaeda and corrupt officials. Hadi, who fought al Qaeda when he had control of the country, says the Islamist militant group is as much a threat to Yemen as it had always been.
The Houthi advance eventually forced Hadi into exile into Saudi Arabia, and Riyadh says it wants to restore Hadi and prevent Yemen disintegrating as a state, with al Qaeda militants thriving in the chaos and one of the world’s busiest oil shipping lanes off the Yemeni coast at risk.
Saudi Arabia last week announced a formal end to the nearly five-week-old campaign but said it would continue to target any attempt by the Houthis to advance further. The bombing eased initially but picked up intensity again on Sunday and Monday.
Fighting pitting the Houthis against Sunni tribesmen and Islamist militants, with army units on both sides, has worsened the humanitarian situation.
Residents of the southern port city of Aden said bread was in short supply and a convoy of trucks carrying flour from the Red Sea port city of Hodeida was being prevented by the Houthis from entering the city.
The Houthis also blocked a convoy of ICRC trucks carrying medical supplies to Aden, but contacts were underway to allow the supplies in.
“Our convoys were blocked from going to Aden and Marib over the weekend and we are in discussions with the Houthis to resolve that,” ICRC spokeswoman Sitara Jabeen told Reuters.
On Sunday, air strikes, naval shelling and ground fighting shook Yemen in some of the most widespread combat since the operations began last month. Residents said there were at least five air strikes on military positions and an area near the presidential palace compound in the Houthi-held capital Sanaa.
Residents also said Saudi-led war planes pounded areas around the presidential compound in Sanaa for the second day, and launched at least five raids on areas under Houthi control in Marib and al-Jouf in northern Yemen.
Heavy clashes also continued in the strategically important central city of Taiz, where armed Sunni tribesmen and Islamist fighters have taken back several districts from the Houthis in heavy fighting, according to residents there.
Residents said street battles were raging in the city of some three million, with both sides using tanks and artillery in residential areas. “The heaviest street fighting is taking place in Taiz. Airstrikes also continued in Aden,” Jabeen said.