SANAA, Yemen — Street battles raged Saturday in the Yemeni port city of Aden as the capital, Sanaa, was bombarded for the first time since Saudi Arabia declared an easing of its air offensive four days earlier.
The Saudi-led coalition’s air war, now entering its second month, has failed to dislodge Shiite Muslim Houthi rebels from Aden, the country’s commercial hub, or wrest control of Sanaa, which fell to the insurgents months ago. The combatants have so far ignored calls to declare a cease-fire and hold peace talks.
More civilian casualties were reported as airstrikes battered the Houthis and their allies in areas including Marib, where major electrical facilities and oil fields are located, and Saada, in the country’s north, where the governor declared Saturday that a full-scale humanitarian crisis had developed.
The United Nations says at least half of the more than 1,000 people believed to have been killed in the last month are civilians.
Close-quarters fighting was said to be taking place in at least two neighborhoods of Aden, in the south, which was the last bastion of President Abdu Rabu Mansour Hadi before a Houthi onslaught forced him to flee the country.
Airstrikes and fighting with heavy weapons have left parts of the city in ruins.
Saturday’s bombing was among the heaviest yet of the air campaign. Saudi Arabia on Tuesday declared that the first phase of its military operation was over, suggesting that it would curtail airstrikes, but they resumed again within hours.
Medical officials said that more than two dozen people from both sides died in Saturday’s violence. The Houthis and some army units loyal to former strongman Ali Abdullah Saleh have been fighting forces that claim allegiance to Hadi.
Saleh has called for a pullback by Houthi insurgents, but the rebels have insisted that the airstrikes stop first.
Yemen is the Arab world’s poorest country, but has a strategic location alongside key shipping lanes.
Its descent into violence has been watched with alarm by regional neighbors, and the combatants have powerful outside backers — the Houthis are aligned with Shiite Muslim Iran, while Sunni Muslim Saudi Arabia wants Hadi restored to power.
The U.S. has been providing logistical support to the Saudi-led coalition.