BAGHDAD —  A homicide bomber blew himself up near a police station northeast of Baghdad on Tuesday, killing at least eight people and wounding 30, police and hospital officials said.

The attack occurred as police were gathered near the main gate of the station in Jalula with Kurdish troops who came to the area as part of a security crackdown, police said.

The dead included four Iraqi police, two Kurdish troops and two civilians, police said.

Ahmed Khatab, a doctor at the local hospital, confirmed the death toll and said eight of the 30 wounded were in critical condition.

Jalula, 68 miles northeast of Baghdad, is a religiously mixed city in the Diyala province, a former al-Qaida in Iraq stronghold that has seen a dramatic drop in violence after an influx of U.S.-led forces but continues to see dramatic attacks.

U.S. commanders have warned that extremists in Iraq still pose a serious threat.