At least 21 people were killed and an additional 46 injured when a suicide bomber targeting a Baghdad memorial service for a Shiite militia fighter killed in battle against ISIS blew himself up Friday.

The bomber detonated his explosive vest at the service in the Iraqi capital's southwestern suburb of Hay al-Amal, a police official said, according to Reuters.

The service was for a member of the Hashid Shaabi, a government umbrella group comprised mostly of Shiite fighters who are regarded as some of the most effective forces in the battle against the Islamic State.

There was no immediate claim of responsibility, but suicide bombings like this are almost exclusively done by Sunni extremists throughout Iraq, most notably ISIS, which considers Shiites to be heretics who have strayed from Islam, according to AFP.

Since the emergence of ISIS, Baghdad has seen near-daily attacks, including roadside bombs, suicide blasts and assassinations targeting Iraqi forces and government officials. Civilians are typically caught in the middle, leading to the deaths of hundreds and the displacement of tens of thousands.

The attack on the memorial wasn't the first to occur in Baghdad on Friday. A roadside bomb detonated at a Shiite shrine in Sadr City earlier, killing at least five and wounding 15, police officials reported, according to the Associated Press.

Hospital officials confirmed the casualty figures, but spoke on the condition of anonymity since they weren't authorized to talk to reporters.