Officials say Shiite rebels seize Yemen's third largest city and its airport

Members of a militia group loyal to Yemen's President Abed Rabbo Mansour Hadi, known as the Popular Committees, chew qat, Yemen's favorite drug, as they sit next to their tank, guarding a major intersection in Aden, Yemen, Saturday, March 21, 2015. Yemen's Shiite rebels issued a call to arms Saturday to battle forces loyal to the embattled President Hadi, as U.S. troops evacuated a southern air base over al-Qaida militants seizing a nearby city, authorities said. (AP Photo/Hamza Hendawi) (The Associated Press)

In this photo taken on Friday, March 20, 2015, militiamen loyal to President Abed Rabbo Mansour Hadi ride on an army vehicle on a street in Aden, Yemen. One of them holds a representation of the old South Yemen flag that was used when southern Yemen was an independent state until 1990. The country's Shiite rebels issued a call to arms Saturday to battle forces loyal to the embattled President Hadi, as U.S. troops evacuated a southern air base over al-Qaida militants seizing a nearby city, authorities said. (AP Photo/Yassir Hassan) (The Associated Press)

In this photo taken on Friday, March 20, 2015, militiamen loyal to President Abed Rabbo Mansour Hadi ride on an army vehicle on a street in Aden, Yemen. The country's Shiite rebels issued a call to arms Saturday to battle forces loyal to the embattled President Hadi, as U.S. troops evacuated a southern air base over al-Qaida militants seizing a nearby city, authorities said. (AP Photo/Yassir Hassan) (The Associated Press)

Yemeni security and military officials say Shiite rebels backed by supporters of former President Ali Abdullah Saleh have taken over the country's third largest city of Taiz and its airport.

The seizure on Sunday comes a day after the rebels, known as Houthis, called for a general mobilization against forces loyal to the embattled current president, Abed Rabbo Mansour Hadi. Hadi had just given a defiant speech challenging the Houthis, his first public address since fleeing the capital and establishing a base in the southern city of Aden last month.

Brig. Gen. Hamoud al-Harathi, commander of special forces units based in Taiz, rejected Hadi's legitimacy as president. Meanwhile, thousands demonstrated in Taiz against both the Houthis and Saleh.