Shiite rebels call for Yemen offensive; U.S. troops evacuate

ADEN, Yemen -- Yemen's Shiite rebels issued a call to arms Saturday to battle forces loyal to the country's embattled president, as U.S. troops evacuated a southern air base over al-Qaida militants seizing a nearby city, authorities said.

The call by the rebels, known as Houthis, for a general mobilization increases the ongoing chaos in Yemen, which grew in September when the Shiite rebels stormed into the capital, Sanaa.

In their statement, the rebels described their coming offensive against security and military institutions loyal to President Abed Rabbo Mansour Hadi as a battle against extremists.

Their appeal came minutes after Hadi gave a speech challenging the Houthis, his first address broadcast to the public since fleeing Sanaa last month. He described the rebels' rule in Sanaa and elsewhere as "a coup against constitutional legitimacy."

The U.S. troops, including Special Forces commandos, were leaving the al-Annad air base near the southern city of al-Houta, Yemeni military and security officials said.

Speaking on condition of anonymity as they weren't authorized to discuss troop movements, the officials did not say whether the troops had left the country.

Some 100 American troops and Special Forces commandos are believed to be stationed there. U.S. officials declined immediate comment Saturday.

The al-Annad base is where American and European military advisers help Yemen battle the country's local al-Qaida branch through drone strikes and logistical support.

Al-Qaida's local branch is considered by Washington to be the group's most dangerous offshoot. The U.S. has carried out a series of drone strikes in Yemen targeting suspected militants. Al-Qaida militants took al-Houta on Friday. Their offensive comes as Shiite rebels hold the capital and nine of Yemen's 21 provinces.

In his address, Hadi declared Aden a "temporary capital" and told the rebels' leader, Abdel-Malik al-Houthi, to stop trying to trick the Yemeni people. He accused Iran of backing the rebels, a claim the rebels deny.