ADEN, Yemen, June 28 (Xinhua) -- At least three policemen were injured when unknown armed men hurled two hand-grenades at a government building in Yemen's southern port city of Aden Thursday morning, a security official said.
A group of unidentified assailants suspected of belonging to an armed faction of separatist Southern Movement threw two home-made grenades on the headquarters of the local government in Mualla district in Aden, the local security official told Xinhua on condition of anonymity.
"Police troops stationed around the government building were attacked by grenades, injuring three policemen," the security official said.
"The unknown gunmen managed to escape after a short shootout with police troops," he added.
Local residents said that "two huge blasts were heard nearby the local council building in Mualla district. Several armored vehicles were deployed instantly across the neighborhood."
"Police cordoned off two main roads and set up checkpoints to search for suspects," they told Xinhua.
Earlier this week, the Yemeni police forces shot dead three southern activists during a pro-secession protest in Aden, which is a main stronghold of youth activists demanding independence for the south.
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.