ADEN (Reuters) - Tribal forces in Yemen's eastern Hadramawt province have taken over two army bases, a day after soldiers there left their posts, and plan to retake the provincial capital Mukalla from suspected al Qaeda fighters, army sources said on Saturday.
They said a tribal alliance took control of the bases in Shihr and Riyan, which lie on the Arabian Sea coast northeast of Mukalla, after the army withdrew from them on Friday.
It was not immediately clear why troops had abandoned Shihr and Riyan, nor why they pulled out of Mukalla after offering relatively light resistance, but their withdrawal highlighted the further collapse of any central authority in Yemen.
That security vacuum may give Al Qaeda in the Arabian Peninsula (AQAP), a powerful regional wing of the global jihadi movement, opportunities to entrench itself further in country's remote eastern reaches.
The United States, which has carried out covert drone strikes on suspected al Qaeda targets in Yemen, withdrew its personnel from the country last month after Houthi fighters pushed south towards the al-Anad military base used by the Americans, 60 km north of Aden.
The Shi'ite Houthi forces, which seized the capital Sanaa six months ago along with soldiers loyal to former president Ali Abdullah Saleh, are fighting supporters of the current president in the southern port city of Aden.
Saudi Arabia and regional Sunni Muslim allies have waged 10 days of air strikes against the Houthis to try to stem their advances and to support President Abd-Rabbu Mansour Hadi, who fled Aden for Saudi Arabia more than a week ago.
In a statement, the tribal alliance said it intended to advance on Mukalla and restore security after suspected al Qaeda fighters drove the army out and ransacked the town, burning buildings and breaking into banks and the main prison.
"The leadership of the tribal alliance of Hadramawt...calls on tribes to mobilize towards Mukalla to keep the peace and stability in Mukalla and other towns in the province," the statement said.
Witnesses and tribal sources said armed men were gathering outside Mukalla, and were waiting for reinforcements before advancing on the town itself.
Suspected al Qaeda fighters stormed Mukalla's prison on Thursday, freeing 150 detainees including a prominent local al Qaeda leader, Khaled Batarfi, Yemeni officials said.
They also broke into banks and set fire to the television broadcasting building, residents said.
(Reporting by Mohammed Ghobari and Mohammad Mukhashaf; Writing by Dominic Evans; Editing by Raissa Kasolowsky)