MOGADISHU, Somalia -- A huge explosion from a truck bomb killed 20 people in Somalia's capital, police said Saturday, as shaken residents called it the most powerful blast they'd heard in years.

The explosion appeared to target a hotel on a busy road in Hodan district and at least 15 people were injured, police Capt. Mohamed Hussein said. Security forces had been trailing the truck after it raised suspicions, he said.

Police said people were trapped in the rubble of the Safari Hotel, which was largely destroyed in the explosion. The hotel is close to Somalia's foreign ministry. Rescue workers were at the scene.

Somalis use a sheet to carry a man wounded in a blast away to an ambulance, in the capital Mogadishu, Somalia Saturday, Oct. 14, 2017. Farah Abdi Warsameh / AP

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.

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Gunshots could be heard at the site, and ambulance sirens wailed across the capital, which has been under tight security with military-manned checkpoints.

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.

Somalis remove the body of a man killed in a blast in the capital Mogadishu, Somalia Saturday, Oct. 14, 2017. Farah Abdi Warsameh / AP

"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 for undisclosed reasons.

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.