At approximately 1700 local time (1400 UTC) on 25 October 2021, an explosion occurred on a public bus traveling along the Masaka-Kampala highway in the district of Mpigi, located nearly 40 km (25 mi) west of the capital Kampala. According to a police spokesman, a suicide bomber detonated the explosives aboard the vehicle that was en route to the western town of Masaka from Kampala. The blast killed the assailant and wounded an unspecified number of passengers. The police spokesman stated that the bomber was a member of the Allied Democratic Forces (ADF) Islamist militant group — which is based in neighboring Democratic Republic of Congo — and was known to authorities. Police officers have arrested three people in relation to the blast. The event followed bomb attack at a restaurant on 23 October in the northern Komamboga suburb of Kampala, for which the Islamic State group claimed responsibility.