Officers said the al Qaeda-linked group’s fighters attacked and overran government forces guarding a bridge at the town’s entrance.
Police captain Farah Ali said the fighters stayed briefly in the town after the attack but then left.
Al Shabaab aims to topple the government and impose a strict interpretation of Islamic law by carrying out frequent gun and bomb attacks on security and government targets.
Somalia, which has had only limited central government since 1991, is trying to reconstruct itself with the help of the United Nations.
