BAGHDAD — Thirty-seven people were killed on Friday in a wave of bombings and attacks across Iraq, and eight soldiers were kidnapped, security officials said.

At dawn, a suicide bomber drove a truck filled with explosives into a police station in northeastern Diyala Province, followed by gunmen who sprayed bullets from speeding S.U.V.s. Eleven police officers were killed, including the commander of the unit, officials said.

In the city of Samarra, north of Baghdad, gunmen in S.U.V.s attacked an army unit, took control and killed five soldiers, while kidnapping eight others and bringing them to an undisclosed location, a police official said. A curfew was imposed in Samarra.

Jafar al-Jibory, a security analyst and an army officer during the Saddam Hussein era, placed blame for the attacks on militants with the Islamic State of Iraq and Syria, a powerful jihadist group once affiliated with Al Qaeda that is also fighting in Syria. Al Qaeda broke with the group in February.