SANAA, Yemen — Saudi-led airstrikes targeted Iran-backed rebels and their allies in Yemen on Wednesday, hours after Riyadh declared an end to a monthlong air campaign that has killed hundreds without dislodging the Shiite rebels in control of the capital and much of the country’s north.

The continuing strikes suggest that the U.S.-backed offensive, aimed at restoring Yemen’s internationally recognized president, is entering a new phase in which military action will be scaled back but not halted.

“If there are any military movements that are suspicious on the ground, the coalition will attack it,” said Riad Kahwaji, director of the Dubai-based Institute of Near East And Gulf Military Analysis. “There will be a support and backup for the (pro-Hadi forces) and those supporting the legal movement in Yemen.”

The air raids hit rebel positions in the southern port of Aden and central city of Taiz as ground fighting between the rebels and their allies against supporters of exiled President Abed Rabbo Mansour Hadi continued in both areas, Yemeni officials said.

The capital, Sanaa, was calm, however, as residents experienced their quietest night in almost four weeks. Thousands of pro-Houthi demonstrators marched, decrying “Saudi and American aggression.”

The strikes in Taiz hit the Shiite rebels, known as Houthis, as they gathered near the old airport to the city’s southeast, officials said. Also targeted was Aden. In both areas, the Houthis are fighting alongside forces loyal to former President Ali Abdullah Saleh.