Iraqi police say at least two people have been killed and 14 wounded when a bomb exploded on a minibus near a Shiite shrine in the holy city of Karbala.

Karbala police spokesman Rahman Meshawi says the blast occurred inside an area surrounded by concrete barriers to protect two of the most revered shrines in Shiite Islam.

Only authorized vehicles are allowed in the area and that raises concern about how the attacker was able to get the bomb through the tight security.

Meshawi says the two killed included a 10-year-old boy.

Karbala is in a relatively peaceful area, but it has been hit by several high-profile car bombings and suicide attacks as well as clashes between rival Shiite factions.