* Al Shabaab say withdrew from city earlier
* Militants vow revenge attacks
* Baidoa seen as most important rebel base after Kismayu
* U.N. approves more peacekeepers (Recasts, adds new rebel, AMISOM, resident quotes)
By Mohamed Ahmed and Abdi Sheikh
MOGADISHU, Feb 22 (Reuters) - Ethiopian and Somali troops seized on Wednesday the strategic city of Baidoa from Islamist militants who deserted their positions but vowed to avenge the loss with “fire and explosions”.
Losing control of Baidoa is a major blow for the al Qaeda-backed al Shabaab rebel group which is also battling Kenyan troops to hold on to territory in southern Somalia and against African Union peacekeepers (AMISOM) around the capital.
The Ethiopian-led offensive came as the U.N. Security Council voted to expand the African Union peacekeeping force by almost half to almost 18,000 soldiers, and on the eve of a conference in London to tackle Somalia’s turmoil.
“Ethiopia and Somalia’s troops will never sleep peacefully in Baidoa,” Sheikh Abdiasis Abu Musab, the spokesman for al Shabaab’s military operation, told Reuters.
“There will be ceaseless fire and explosions. Baidoa will be a cemetery for the Ethiopians,” he said. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TAKE A LOOK-Somali turmoil targeted in UK conference
Rebel fighters pulled out of Baidoa earlier on Wednesday in what they suggested was a tactical retreat aimed at avoiding casualties. The insurgents now surrounded the city, Musab said.
Located about 250 km northwest of Mogadishu, Baidoa is considered the most important rebel base after the southern port city of Kismayu.
Baidoa hosted Somalia’s interim government from early 2006, when another Islamist administration was battling warlords for control of Mogadishu, until the turn of 2008/2009 when al Shabaab expelled the transitional authority.
“Baidoa is under our control,” said Abdifatah Mohamed Gesey, governor of Bay region. “We are going to hunt them down in every pocket of this region.”
Somalia’s Prime Minister Abdiweli Mohamed Ali hailed the capture of Baidoa, a city of an 800,000 people he described as “one of the most important” in southwestern Somalia.
Ethiopia sent troops across the border into Somalia in November to open up a third front against the militants already suffering financial constraints and internal divisions.
Its ground-forces launched a push south towards Baidoa through Bay and neighbouring Bakool regions on Tuesday and faced minimal resistance, said officials.
On Wednesday morning, witnesses said al Shabaab had also surrendered the town of Berdale about 60 km from Baidoa, a day after losing control of the town of Yurkud about 50 km away.
After a day hunkered down in fear of a bloody battle for Baidoa, residents remained hesitant to wander far.
“Our movement is very limited. The government and Ethiopian troops are jointly patrolling every corner of the town,” resident Moalim Ali Aden told Reuters by telephone from Baidoa.
It was not immediately clear how long Ethiopia would keep its forces deep inside Somalia.
Ethiopia’s more than two-year military presence inside Somalia between late 2006 and early 2009, when it routed another Islamist administration from power, provoked massive resentment and galvanised support for the militant Islamists.
Increasing the cap on AMISOM’s numbers to 17,731 paves the way for Kenya’s troops in southern Somalia to “re-hat” as peacekeepers and for the peacekeeping force to move decisively beyond the confines of Mogadishu.
Diplomats, however, say Ethiopia’s troops will not integrate into AMISOM and will eventually withdraw.
“Al Shabaab will have no place in Somalia. They are already weakened and we shall finish them,” AMISOM force spokesman Paddy Ankunda told Reuters. (Additional reporting by Feisal Omar; Writing by Richard Lough; Editing by Roger Atwood)