Mogadishu, Somalia (CNN) -- Al-Shabaab militants killed at least 12 people Tuesday in a car bombing and assault on a police station shared by African Union peacekeepers in a key Somali commercial hub, authorities said.
At least four of the Islamist attackers also were killed as Somali police and AU troops responded to the assault on the police station in Beledweyne, about 200 miles north of the Somali capital of Mogadishu, said Abdi Farah Laqanyo, governor of the Hiran region.
The attack is the latest on Somali and AU forces by Al-Shabaab, a group that is fighting the government in hopes of turning Somalia into a fundamentalist Islamic state.
A car packed with explosives was driven into the station's gate and burst "into a huge ball of flames" about 11 a.m., Laqanyo said.
Attackers then entered the police compound and exchanged fire with police and AU forces, authorities said. The station is a base for Djiboutian troops serving as peacekeepers for the African Union Mission in Somalia, known as AMISOM, which supports Somali forces in cracking down on Al-Shabaab.
The attack killed at least 10 defenders -- six Somali policemen and four Djiboutian soldiers with AMISOM -- said Col. Abdilkadir Osman, a police officer in the town. Two civilians also were killed, authorities said.
A spokesman for Al-Shabaab's military operations, Sheikh Abdiaziz Abu Musab, said the group carried out the attack. Abu Musab claimed the attack killed 18 AMISOM troops and 23 Somali forces, though CNN could not independently verify that count.
A witness who was 200 meters from the site said the attackers used assault rifles, machine guns and rocket-propelled grenades after the car bombing. The witness, speaking on condition of anonymity, said a plume of black smoke rose from the police station.
Tuesday's fighting comes less than a month after a suicide attack claimed by Al-Shabaab killed 16 people at a cafe in Beledweyne.
Somali President Hassan Sheikh Mohamud said Tuesday he was sending condolences to the victims of what he said was a "stupid attack."
"I say this was a stupid attack because our enemies need to understand that these attacks do nothing to advance their cause, however misguided," Mohamud said. "We are making great progress while our enemies are on the back foot and reduced to sporadic and self-defeating attacks with no regard to life."
Beledweyne is the capital of the Hiran region. Situated near the Ethiopian border, it is a commercial hub linking southern and northern Somalia.
Though Al-Shabaab is fighting the Somali government, it has launched attacks in other countries as well, and it has a relationship with al Qaeda that goes back several years. Al-Shabaab claimed responsibility for September's four-day siege at the Westgate Mall in Nairobi, Kenya, where at dozens of people were killed.
The U.S. government designated Al-Shabaab as a foreign terrorist organization in March 2008.
Journalist Omar Nor reported from Mogadishu. CNN's Jason Hanna wrote from Atlanta. CNN's Nana Karikari-apau contributed to this report.