NAJRAN, Saudi Arabia — Saudi Arabia declared an end on Tuesday to its nearly monthlong “Decisive Storm” air campaign against Houthi rebels in Yemen, and announced the start of a more limited military campaign aimed at preventing the rebels from operating.

Speaking at a news conference in Riyadh, spokesman for the Saudi-led coalition Brig. Gen. Ahmed Asiri said the campaign of heavy airstrikes would be scaled down, but did not confirm whether they would stop altogether.

“There might be less frequency and the scope of the actions might be less, but there will be military action,” Asiri said.

He said the goals of the coalition’s new phase, called “Renewal of Hope,” are to prevent Houthi rebels from “targeting civilians or changing realities on the ground.”

The U.S.-backed campaign by Saudi Arabia, which was launched March 26, was aimed at crushing the Houthis and allied military units loyal to former autocratic Yemeni President Ali Abdullah Saleh, who had taken over the capital of Sanaa and much of northern Yemen. The kingdom says the aim is also to restore to power President Abed Rabbo Mansour Hadi, who was forced to flee Yemen to Saudi Arabia last month.

Asiri said that Saudi Arabia and its coalition allies, mainly Gulf Arab countries, were concluding this phase of the operation upon the request of the “legitimate” Yemeni government, led by Hadi.

Hadi, in a speech broadcast after midnight on Saudi network Al-Arabiya and Qatar’s Al-Jazeera, thanked his Saudi allies for supporting his “legitimacy” as president of Yemen.

Al-Qaida in Yemen has made tactical gains amid the chaos. The ground fighting and airstrikes have pushed Yemen, the Arab world’s poorest country, to the brink of collapse. The fighting has also taken on the appearance of a proxy war between Iran, the Shiite powerhouse backing the Houthis, and Sunni-dominated Saudi Arabia.

The Houthi militias are active in the southern port city of Aden, which has seen fierce fighting and the shelling in recent weeks. Earlier Tuesday, the coalition pounded Houthis and their allies, killing 20 fighters in the western city of Ibb, where Yemeni security officials say the rebels were assembling to head to Aden as reinforcements against forces loyal to Hadi.