As many as nine people were wounded on Wednesday when Yemeni security forces clashed with separatists in the southern port city of Aden, witnesses told Xinhua.

The secessionist gunmen attacked security troops stationed near a pro-secession protest square in the Mansoura district in Aden, sparking a short gunbattle that left about nine people injured, including three soldiers, the witnesses said on condition of anonymity.

"Security troops fired back with heavy machine-guns," the witnesses said.

"Snipers were seen firing from rooftops at the gunmen who managed to flee the area later," they added.

A medic official at the Naqeeb hospital confirmed to Xinhua the figure of the injured.

"Police arrested three members of the secessionist armed faction in Aden's Mansoura neighborhood who are accused of conducting saboteur acts," a security official said anonymously.

Earlier this week, three protesters were killed and several others injured during a rally in Aden which is a main stronghold of youth activists demanding independence for southern regions.

North and South Yemen unified peacefully in 1990, but the relationship deteriorated in 1994. Calls for separation in the country's southern regions were renewed in 2007.