A huge explosion from a truck bomb rattled Somalia’s capital Saturday, killing at least 20 people and injuring more than a dozen.

The explosion appeared to target a hotel on a busy road in Hodan district of Mogadishu as residents called it the most powerful blast they’d heard in years.

Police Capt. Mohamed Hussein said security forces had been trailing the truck after it raised suspicions.

The sound of ambulance sirens could be heard across the capital, and gunfire was heard at the site of the blast.

The explosion left a trail of destruction across a busy intersection, with several bodies and bloodied slippers and shoes. Windows of nearby buildings were shattered. Overturned cars lay in the street, burning. A large plume of smoke rose nearby.

"There was a traffic jam and the road was packed with bystanders and cars," said Abdinur Abdulle, a waiter at a nearby restaurant. "It's a disaster," he said sadly.

The blast occurred two days after the head of the U.S. Africa Command was in Mogadishu to meet with Somalia’s president, and two days after the country’s defense minister and army chief resigned.

The Somalia-based extremist group al-Shabab recently stepped up attacks on army bases across south and central Somalia. While there was no immediate claim of responsibility for Saturday's blast, al-Shabab often targets high-profile areas of Mogadishu with deadly bombings.

The U.S. military has stepped up drone strikes and other efforts this year against the al-Qaida-linked al-Shabab, which is also fighting the Somali military and over 20,000 African Union forces in the country.

The Associated Press contributed to this report.