Al-Qaida militants carried out a number of armed attacks targeting Yemen's largest military air base of al-Anad in southern province of Lahj on Wednesday after a series of offensive attacks at police stations and intelligence headquarters earlier in the day, a local military official told Xinhua.

A security official in Houta, the provincial capital city of Lahj, told Xinhua that "armed militants believed to be from al- Qaida wing opened heavy fires on security guards of some government buildings, including police stations, intelligence headquarters and banks, in the city at Wednesday dawn."

A local resident named Nabih said that electricity supply was cut in the city during the clashes, in which sounds of machine guns and mortars were heard, while people were fearing going outside and many shops and markets closed.

Groups of al-Qaida militants also attacked the al-Anad military air base located to the northeast of Aden province from several directions with heavy machine guns and rocket-propelled grenades, the official told Xinhua on condition of anonymity, adding that fierce clashes are still going on between the two sides after the militants withdrew and then struck back.

Meanwhile, a local doctor at the Ibn Khaldoon hospital said on condition of anonymity that four soldiers were killed and dozens of others injured were receiving treatment at the hospital.

Armed gunmen believed belonging to al-Qaida were seen marching the streets of Lahj province, Wadhah Omar, according to a local resident.

A post office and several banks were completely destroyed after the looting acts by al-Qaida militants, Omar said, adding that all the contents of that banks were taken by al-Qaida.

Al-Qaida in the Arabian Peninsula (AQAp) has intensified their activities in southern provinces of the impoverished Arab country as its cash-stripped government was in the grip of five-month-long protests demanding the ouster of President Ali Abdullah Saleh.

Late in May, the Yemen-based al-Qaida wing took over all parts of southern Abyan province and declared the city of Abyan as the capital city of its "Islamic Emirate" in a statement the group read in front of local residents.

Gulf countries and western community fear that unrest in Yemen could make it as strong footholds for the terrorist groups that would possibly threaten one of the world busiest oil shipping lanes in the Gulf of Aden and Red Sea.