Yemeni security forces on Friday opened fire to disperse a pro-secession protest in the southern port city of Aden, leaving at least three people injured, witnesses told Xinhua.

Dozens of soldiers fired tear gas at the pro-secession southern protesters to disperse them before firing live rounds, injuring at least three people in Aden's neighborhood of Cerater, the witnesses said, requesting anonymity.

"Some of the protest organizers were injured," the witnesses said, adding that the security soldiers had also arrested some of the wounded, preventing them from going to hospitals for treatment.

A leader of the pro-secession Southern Movement told Xinhua anonymously that "the security soldiers confronted some 300 protesters who had taken to the streets after weekly prayers in downtown Aden."

"The situation in many neighborhoods of Aden is very tense and we will escalate our peaceful demonstrations against the security troops," he added.

The port city of Aden is a main stronghold of youth activists demanding outright independence for the south.

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

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.

The United States has become increasingly concerned that the conflicts in south Yemen, which are creating an unstable state where al-Qaida could more freely operate to gain territorial foothold.