Somali militant group al-Shabab has resumed radio broadcasts in the key port city Kismayo, vowing to fight to the death against pro-government forces poised to move in.

The group's radio station, Andalus, went back on the air Wednesday morning, two days after going quiet as government and African Union forces advanced on the town.

The al-Qaida-allied group urged residents in Kismayo — the militants' largest remaining stronghold — not to flee and to remain calm.

Witnesses reported seeing armed trucks belonging to al-Shabab throughout Kismayo on Wednesday.

Somali government and African Union forces, meanwhile, say they remain stationed about 60 kilometers outside the city and ready to move in.

Speaking to VOA from the front line, Somali military Colonel Warfa Sheikh Adan said forces could move in within hours, but said it may be days.

He said residents need not fear allied troops. And he urged them to remain in the city but to stay away from al-Shabab-controlled areas.

Witnesses say residents continued to flee Kismayo on Wednesday.

The U.N. refugee agency says so far this month about 6,500 residents have fled the coastal city.

Al-Shabab has used the town's seaport to bring in weapons and other supplies to support their battle against the government.

The extremist group is seeking to impose a hardline form of Sharia throughout Somalia. It once controlled most of southern and central Somalia, but has lost most of its territory to pro-government forces.