The killing of the pilgrims underscored the danger of sectarian violence in Iraq, while the attacks on the city council and police station in Salaheddin province showed the impunity with which militants can strike even targets that should be highly secure.
Violence in Iraq has reached a level not seen since 2008, when the country was emerging from a period of brutal sectarian killings, and has raised fears it is slipping back into all-out conflict.
Sunni militants including those linked to Al-Qaeda frequently target members of Iraq's Shiite majority, whom they consider to be apostates.
In the city of Tikrit, militants detonated a car bomb near the city council headquarters and then occupied the building, with employees still inside.
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Iraqi security forces surrounded the building, and then carried out an assault that Counter-Terrorism Service spokesman Sabah Noori said freed 40 people who were held inside.
"We freed all the hostages" and killed one suicide bomber, while two others blew themselves up, Noori told AFP.
The assault came after suicide bombers struck a police station in the town of Baiji, also in Salaheddin province.
One bomber detonated a car bomb at the gate of the station, after which three entered, shot dead an officer and a policeman, and waited inside.
SWAT security forces then attacked the station, killing one of the militants, while the other two blew themselves up, killing three police.
The second-deadliest attack today was in the northern city of Mosul, where militants gunned down 12 people on a bus.
Also today, five other car bombs and a magnetic "sticky bomb" on a vehicle exploded in and around the Iraqi capital, killing at least 17 people and wounding at least 43 -- the second series of blasts in the area in 24 hours.