According to Lt. Apollo Mwanamboka, a security officer in eastern Congo, the blast took place at the Spak Church in the town of Kasindi in the restive North Kivu province, less than a mile away from the Mpondwe border post with Uganda.
Julius Kasake, an eyewitness, said he was passing near the church when he heard a noisy blast. He said people from nearby homes ran into the church to help those hit by the blast.
Congo Army spokesman Anthony Mualushay said the attack was likely carried out by the Allied Democratic Forces (ADF), a Ugandan terrorist group that has allegiance to the terrorist group Daesh/ISIS.
The army in Uganda immediately beefed up security at the border post and the surrounding areas.
The ADF was formed in Uganda in the late 1990s with the main intention of overthrowing the president. Overpowered by the Ugandan army, its fighters fled into Congolese forests, where they attacked innocent civilians.