In the northern city of Mosul, gunmen broke into the houses of two Shabak families, killing a boy and his parents in one and a mother and daughter in the other, according to police. A bomb exploded near the house of another Shabak family, wounding six family members.
Shabaks are ethnically Turkomen and Shiite by religion. Most Shabaks were driven out of Mosul by Sunni militants during the sectarian fighting a few years ago.
In Tuz Khormato, about 210 kilometers (130 miles) north of Baghdad, a car bomb exploded near in a neighborhood with a Turkomen Shiite majority. Mayor Shalal Abdoul said 11 people were wounded, including three children.
Medics in nearby hospitals confirmed the casualties. All officials spoke on condition of anonymity because they were not authorized to talk to the media.
Eid al-Adha, or Feast of the Sacrifice, is a major Muslim holiday that commemorates what Muslims believe was the Prophet Abraham's willingness to sacrifice his son Ismail, the Biblical Ishmael, as a test of his faith from God. Christians and Jews believe another of Abraham's sons, Isaac, was the one almost sacrificed.
The holiday, which began Friday, marks the end of the hajj pilgrimage to Mecca. Muslims worldwide typically slaughter lambs and other animals to commemorate the holiday, sharing some of the meat with the poor.
Violence has ebbed across Iraq, but insurgents frequently attack security forces and civilians in an attempt to undermine the country's Shiite-led government.
Holidays are a particular time of concern for security forces. A wave of attacks shortly before another Muslim holiday in August, Eid al-Fitr, killed more than 90 people in one of the deadliest days in Iraq this year.
Associated Press writer Sameer N. Yacoub contributed reporting.