Mr. Hadi became president through a transitional pact brokered by Saudi Arabia and its Persian Gulf neighbors to remove Mr. Saleh and quell an Arab Spring uprising against him. But the Saleh and Houthi forces put him under house arrest in Sana until he escaped last month to make a last stand among his supporters in the southern port of Aden.

Then, as the Houthi and Saleh forces closed in on Aden, Mr. Hadi disappeared again last Wednesday, turning up the next day in Saudi Arabia, then at a conference in Sharm el-Sheikh, Egypt, and on Saturday, again, in Saudi Arabia.

In his speech, Mr. Saleh called for elections to choose a new president, saying, “We would vote for him just as did with Hadi.”

“I appeal to you and your conscience to protect your children and women in Yemen against these barbaric and unjustified strikes,” he said in his speech, apparently addressing both Yemenis and the Arab leaders lined up behind the Saudi Arabian-campaign against him.

The Houthi movement, based in northwestern Yemen, follows a form of Shiite Islam and has received financial support from Iran, the region’s Shiite power and the chief rival to Saudi Arabia. That is what has alarmed the Saudis, who fear an Iranian-backed group digging in on the southern tip of the Arabian Peninsula.

Diplomats say that Iran has given money to the Houthis but does not control the group. But Mr. Hadi on Saturday called the Houthis “stooges of Iran.” Speaking at an Arab League meeting in Sharm el-Sheikh, Mr. Hadi urged Saudi Arabia and its allies to continue bombing until the Houthis surrendered, withdrew from the cities and turned over their weapons.

Saudi Arabia said on Saturday that its navy had evacuated 86 Arab and Western diplomats from Aden, which Mr. Hadi had made his provisional capital. Air travel to Yemen has been cut off, and the Saudi Arabian coalition has blockaded the coast.

Residents of Aden, with a population of at least several hundred thousand, said on Friday that fighting had broken out in pockets around the city. Military forces nominally working for Mr. Hadi had switched sides or deserted as the Houthis advanced. Looters were pillaging arms from military bases. Local militias with no affiliation with Mr. Hadi’s government were arming themselves to defend their neighborhoods or fight the Houthis.