At least 10 people were killed when a passenger bus hit an improvised explosive device (IED) on a highway in northeastern Kenya, police said on Monday.

Eight passengers were injured in the explosion, which occurred when a bus ran over an IED on the Arabia-Mandera highway, according to George Seda, a regional police commander.

Police have believed the bomb was planted by the Somalia-based al-Shabaab terror group.

The Somalia group which is linked to the al-Qaeda terror network has carried out several attacks in Mandera, a Kenyan border town which is just about 370 kilometers (230 miles) from Somalia’s capital Mogadishu.

Seda has said security forces have been deployed in the area to track down the attackers, but no arrests have been made yet.

Monday’s blast has come after several Western countries issued a terror warning for Kenya over the weekend.

Kenyan authorities had responded to the advisory by scaling up to security operations in vulnerable areas.

Past Attacks

Al-Shabaab terrorists have carried out several such IED attacks in Kenya, targeting security patrols on key routes along the porous Kenya-Somalia border, according to Kenyan authorities.

The latest incident was on Jan. 7, when four police officers were killed in an al-Shabaab attack in the town of Lamu, along the East African coast.

That came just over a month after two police officers were killed 12 others injured in an al-Shabaab ambush in Mandera.

In 2018, more than 100 Kenyan police personnel were killed in IED attacks along the border, according to Kenyan government data.

Kenya has now signed a deal with Turkiye in January 2021 to procure 118 high-performance armored personnel carriers to protect its troops from “vehicle-borne IEDs (VBIEDs), IEDs and directional explosives.”