Somali officials say nine civilians were killed and 10 others were wounded in a roadside bomb explosion outside Mogadishu on Sunday.

The blast from an improvised explosive device hit a bus transporting civilians from Mogadishu to the town of Wanlaweyn, 90 kilometers west of the capital.

The Somali government says al-Shabab is responsible for the attack.

"The federal government of Somalia condemns the barbaric act of terrorism committed against the Somali civilians," read a statement issued by the Ministry of Information.

Governor of Lower Shabelle region Ibrahim Aden Najah told VOA Somali that seven victims died on the spot while two others died in hospitals. He said there were a total of 22 people in the bus and only 3 people escaped unharmed.

Al-Shabab has been known to plant IEDs in the area of the explosion known as Hawa Abdi, about 18 kilometers west of Mogadishu, to target the Somali military and African Union peacekeepers. These IEDs often miss their targets and kill civilians.

Al-Shabab has been using IEDs increasingly in its attacks in Somalia. Last week, 14 government soldiers were killed in two separate IED attacks in Middle Shabelle and Lower Shabelle regions. Al-Shabab claimed responsibility for both attacks.

The Director of the U.N. Mine Action Service Agnès Marcaillou told the U.N. Security Council earlier this month that there more than 160 IED attacks through the end of April in 2020.

The U.N. has reported a drop in civilian casualties in Mogadishu this year, which was attributed to the current security plan and military operations in the neighboring Lower Shabelle region.