Somalia's Al-Qaida-affiliated Shebab militants on Thursday attacked a fortified area in the central town of Baidoa, home to a key regional government headquarters, United Nations compound and airport, security officials said.

Officials said five gunmen opened fire at the gate of the high-security zone but were held off by Ethiopian and Somali government troops. A source said an Ethiopian soldier was killed, while three of the attackers blew themselves up, another was shot dead and the fifth was shot and wounded, ending the attack.

Al-Qaida-linked Somali militants vowed Saturday to intensify the war against government and African Union troops, despite the fall of their key stronghold of Afgoye, the latest in a string of military losses.

"God willing we will continue the war and we will win the battle without doubt," said Sheik Abdiaziz Abu Musab, spokesman for the hardline Shebab, a day after AU and Somali troops entered Afgoye, a former strategic rebel base.

The walls of the former Shebab base in Baidoa, Somalia, are littered with rudimentary drawings of machine guns and tanks, a note reading "Fear God, don't write on these walls" and a sketch of an al-Qaida flag, homage to the rebel group's international allies.

The crumbling building is now occupied by Ethiopian troops who nearly two weeks ago forced Shebab rebels out of Baidoa, their former Shebab stronghold and Somalia's third-largest city. It is the second time Ethiopia has occupied Baidoa after pulling out of Somalia in 2009 following a bloody two-year war.

Two heavy blasts rocked the strategic Somali city of Baidoa hours after Ethiopian and pro-government forces wrested it from al-Qaida-allied Shebab insurgents, officials and witnesses said Thursday.

"Heavy losses were inflicted on the enemy after two explosions struck them when they entered positions our fighters had emptied," Shebab spokesman Sheikh Abdulaziz Abu Musab said, claiming responsibility for the blasts.

Truckloads of Ethiopian and Somali troops on Wednesday captured the strategic Somali city of Baidoa from Al-Qaida-allied Shebab insurgents, who vowed to avenge the loss.

"We have taken control of Baidoa without a single shot, it is a great day for the people who are now welcoming us warmly," said Muhidin Ali, a Somali government military commander in Baidoa.