SANAA, Yemen (AP) - Yemen's embattled president fled his palace in Aden for an undisclosed location Wednesday as Shiite rebels offered cash bounty for his capture and arrested his defense minister.

President Abed Rabbo Mansour Hadi left just hours after the rebels' own television station said they seized an air base where U.S. troops and Europeans advised the country in its fight against al-Qaida militants. That air base is only 60 kilometers (35 miles) away from Aden, the port city where Hadi had established a temporary capital.

The advance of the Shiite rebels, empowered by backing of the ousted Yemeni autocrat Ali Abdullah Saleh's loyalists, threatens to plunge the Arab world's poorest country into a civil war that could draw in its Gulf neighbors. Already, Hadi has asked the United Nations to authorize a foreign military intervention in the country.

Witnesses said they saw a convoy of presidential vehicles Wednesday leaving Hadi's palace, located at the top of a hill in Aden overlooking the Arabian Sea.

Presidential officials said Hadi was in an operations room overseeing his forces' response. They declined to say where that facility was located. The officials spoke on condition of anonymity as they weren't authorized to brief journalists.

Yemen's Foreign Minister Riad Yassin told Dubai-based Al-Arabiya TV satellite news network that he officially made a request to the Arab League on Wednesday to send a military force to intervene against Houthis. Yassin is attending the Arab Summit due to take place in Egypt at the end of the week.

Depicting the Houthis as a proxy of Shiite Iran, a rival to Sunni Gulf countries, Yassin warned of Iranian “takeover” of Yemen. The Houthis deny they are backed by Iran.