Updated

A least nine people were killed in an attack on Somalia's interior ministry and security forces continued to battle gunmen inside, police said Saturday, as the al-Shabab extremist group claimed responsibility.

Gunfire could be heard amid reports that a number of people, mostly government workers, were trapped in the ministry on what had been a normal business day.

More than 10 people were wounded and the death toll could rise, Col. Ahmed Mohamed said. Witnesses said some ministry staffers died or were injured while leaping from windows or walls in an effort to escape.

The attack began in the morning when a suicide car bomber detonated at the gate of the interior ministry, which is close to the presidential palace and the headquarters of parliament, police Capt. Mohamed Hussein told The Associated Press.

Three gunmen were believed to be holed up inside the ministry, Hussein said as shooting could be heard in the background. The compound also holds Somalia's security ministry.

Ambulance sirens echoed across the area as soldiers opened fire to disperse bystanders and motorists.

The Somalia-based al-Shabab, an arm of al-Qaida, often targets high-profile areas of the capital. It was blamed for the October truck bombing that killed more than 500 people in the deadliest attack in the country's history.

The ongoing threat from what has become the deadliest Islamic extremist group in sub-Saharan Africa has hurt efforts to strengthen Somalia's fragile government and stabilize the long-chaotic Horn of Africa nation.

The United States under the Trump administration has stepped up military efforts in Somalia, including dozens of drone strikes, against al-Shabab and a small presence of fighters linked to the Islamic State group. At least two U.S. military personnel have been killed.

The U.S. military and others in the international community have expressed concern about the plan for Somalia's security forces to take over the country's security from a multinational African Union force over the next few years, saying the local troops are not yet ready.