Yemeni security forces detained Monday five pro-secession youth activists during a mass separatist protest held in the southern port city of Aden, residents told Xinhua.

Two prominent leaders of the pro-secession Southern Movement were among those detained in Aden's neighborhood of Mansoura when the security forces moved in to break up the rally, one of the local residents said, requesting anonymity.

The arrests took place just few hours after clashes between security troops and separatists in downtown Aden, the capital of the formerly independent South Yemen, the resident said.

Elsewhere in Aden, unidentified gunmen fired at a police station in the Cerater neighborhood and threw two home-made bombs while riding motorcycles, a police officer told Xinhua anonymously.

Security soldiers responded with machine gun fire, the police officer said. No casualties were reported.

The Southern Movement kicked off Sunday its first meeting calling for independence for the south from the central government in Sanaa, amid the boycott of more than 20 senior separatist leaders.

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.

Southerners have complained of being marginalized, particularly since they lost the four-month civil war in 1994.

Pro-secession protests have multiplied in the south amid a worsening economic situation in Yemen and charges of discrimination in favor of northerners.