Khaled Abdullah / Reuters
The historical Radda castle, above, was overtaken by al-Qaida militants on Sunday.
SANAA, Yemen -- Islamist militants have seized full control of a town southeast of Yemen's capital, raising their flag over the citadel, overrunning army positions, storming the local prison and pledging allegiance to al-Qaida leader Ayman al-Zawahri, residents said Monday.
The capture of Radda in Bayda province, some 100 miles south of capital Sanaa, underscores the growing strength of al-Qaida in Yemen as it continues to take advantage of the weakness of a central government struggling to contain nearly a year of massive political unrest.
"Al-Qaida has raised its flag over the citadel," one resident told Reuters by telephone. "Its members have spread out across the town's neighborhoods after pledging allegiance to Ayman al-Zawahri during evening prayers (on Sunday)."
After months of street protests demanding he step down, Yemen's President Ali Abdullah Saleh has signed an agreement transferring power to his vice president. NBC's Savannah Guthrie reports.
Bayda province is a key transit route between the capital and Yemen's southern provinces where the al-Qaida militants are most active. Islamist militants have already seized control of a swath of territory and towns in Abyan province in southern Yemen.
An Associated Press photographer who visited Radda on Sunday said the militants were armed with rocket-propelled grenades, automatic rifles and other weapons. He quoted residents as saying the black al-Qaida banner has been raised atop the mosque they captured over the weekend.
The move is likely to raise concern in neighboring Saudi Arabia, the world's top oil exporter, and the United States about al-Qaida's spreading presence in Yemen, which lies next to important oil and cargo shipping lanes in the Red Sea.
Washington and Riyadh are pushing for implementation of a deal signed in November under which Yemeni President Ali Abdullah Saleh formally handed power to his deputy to calm unrest and restore order in the impoverished country.
Radda residents said the militants, who stormed the town of 60,000 people overnight Saturday, had killed two policemen, seized the local prison and five police vehicles and were besieging government buildings.
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Reuters and The Associated Press contributed to this report.