Local army spokesman Anthony Mwalushayi told Reuters the number of casualties had increased to 14 deaths and 63 wounded, from five and 15, respectively, announced on Sunday.
Islamic State claimed responsibility for the attack on a Sunday service at a Protestant church in the eastern city of Kasindi, near the border with Uganda.
The army had blamed the attack on the Allied Democratic Forces (ADF), a Ugandan militant group that pledged allegiance to the Islamic State in 2019. The militant group could not be reached for comment and did not claim responsibility for the bombing.
Kasindi is in a province where Congolese and Ugandan forces have launched a campaign against the ADF, which began as an uprising in Uganda but has been based in Congo since the late 1990s.
The group has been accused of killing hundreds of villagers, sometimes with machetes, in frequent raids over the past two years.
