Iraqi police say a truck bomb killed 37 people and wounded more than 60 outside a Sunni mosque Saturday in restive Anbar province.
Separately Saturday, the U.S. military says eight Iraqi police officers were killed in an insurgent attack on a checkpoint near Baghdad's airport.
In a statement, the military said at least two insurgents were killed in the ensuing gunbattle.
Elsewhere in Baghdad, an Iraqi official says a suicide car bomber Saturday attacked a checkpoint near the house of a powerful Shi'ite leader, killing one guard and wounding several others.
The interior ministry source said the violence occurred near the compound of Abdul Aziz al-Hakim, whose son is at the center of recent controversy.
Iraqis Saturday rallied in several Shi'ite cities and towns - including Najaf, Basra and Karbala - to protest the brief detention by U.S. troops of Hakim's eldest son, Amar.
On Friday, Amar al-Hakim was detained at a border checkpoint when he returned from a trip to Iran. He was released later the same day.
The U.S. military says Amar al-Hakim's convoy was stopped because the vehicles met "criteria for further investigation" in an area known for smuggling. The military says he was detained when members of the convoy failed to cooperate and acted suspiciously.
U.S. officials have apologized for the incident, and said the United States meant no disrespect to the Hakim family.Some information for this report was provided by AFP, AP and Reuters.