One soldier was killed and a number of separatists and troops were wounded at Sunday dawn in a battle that erupted after armed separatists attempted to raid an army base in Jahaf district in the southern province of al-Dhalee, where the secessionist sentiment is running high, said the army officer.

"Diversified heavy weapons were used during the battle that began early Saturday night and as if ended Sunday morning," said the official.

The officer, who requested not to be identified because he is not authorized to speak to media, refused to give further information.

Elsewhere in Lahj, a southern province located between al- Dhalee and the city port of Aden, hundreds of southern armed tribesmen besieged the main building of the security headquarters on Sunday over killing four soldiers of their kinsmen last week, said a source at the Interior Ministry in Sanaa, the capital.

"The four soldiers, who belonged to the angry armed tribe of al- Sabiha, were killed by southern separatists while they were in a mission to chase saboteurs in Helya area on July 27," the source told Xinhua on condition of anonymity.

"Hundreds of tribesmen of al-Sabiha tribe demanded the security authorities to hand over the suspected-perpetrated killers," he said.

"The director of the security headquarters there made a deal with the angry tribe, under which a large security campaign has been dispatched to arrest the suspected killers and bring them to justice," the source added.

Voices to secede the southern part of the country from the north increased recently along with separatist ambushes and clashes against government troops which lead to many fatalities on both sides.

Northern and southern parts of Yemen were unified in 1990 according to a deal between the People's General Congress and the Yemeni Socialist Party. However, the deal fell apart, leading to a crisis between the two allies, which developed into a civil war in 1994.

Xinhua