(CNN) -- Eight people were killed on Thursday in shootings and bombings across Iraq, police in Tikrit said.
Two car bombs exploded in Tuz Khurmatu, an ethnically tense city in the northern province of Salaheddin, and killed three people. The bombs, which exploded in a Turkmen residential area, also wounded 27 people. The city also has significant Kurdish and Arab populations.
Gunmen in Baghdad shot dead three people, Baghdad police said. Two men were shot and killed in the northern city of Mosul, police there said.
Violence has been on the upswing in Iraq since spring as tensions have grown, particularly between the country's Shiite majority and its Sunni minority. More than 6,000 people have been killed this year, including more than 350 this month.
Iraqi Prime Minister Nuri al-Maliki, who is Shiite, touched on the violence in a New York Times op-ed column this week.
"Imagine how Americans would react if you had a terrorist organization operating on your own soil that killed dozens and maimed hundreds every week. For Iraqis, that isn't a hypothetical question; Al Qaeda in Iraq and its affiliates are conducting a terrorist campaign against our people," he wrote.
Al-Maliki is in the United States for a meeting with President Barack Obama to plan "a deeper security relationship" with Washington to fight terrorism and deal with regional security issues.