(CNN) -- A wave of violence swept across Iraq on Friday, resulting in at least 38 deaths, police said. Most of the casualties occurred in Sunni towns and cities, according to police in Baquba, Ramadi, Mosul, Samarra, Kirkuk and Tikrit.
• The deadliest attack occurred about 105 miles (170 kilometers) north of Baghdad in Anjana, where a suicide bomber drove a truck loaded with explosives into federal police headquarters, police officials in Tikrit and Baquba said. Officers were among the 14 people who were killed and 18 others wounded, the officials said.
• In al-Dibis, about 186 miles (300 kilometers) north of Baghdad, at least two people were killed and 28 others wounded when two car bombs exploded near where people in the streets were celebrating Nowruz, a Persian new year festival marking the arrival of spring, police officials in Kirkuk said.
• At least six people were killed and 40 others wounded when a suicide bomber detonated his explosive vest among dozens of mourners attending a funeral inside a building in central Ramadi, about 62 miles (100 kilometers) west of Baghdad, police officials said.
The funeral was for a leader of a local Awakening Council who had been killed Thursday when a roadside bomb exploded near his car, also in Ramadi.
As mourners gathered in the aftermath of Friday's attack, another suicide bomber detonated a bomb, resulting in dozens more casualties, police said without providing specifics.
Awakening Councils, also known as the Sons of Iraq and Sahawat, are composed primarily of Sunni Arab fighters who turned against al Qaeda in late 2006. The U.S.-backed movement is credited with having contributed to a drop in violence across Iraq, but council members have become targets for remaining jihadists.
Ramadi is a predominantly Sunni city in Anbar province that has seen intense fighting between Sunni extremists and Iraqi security forces aligned with tribesmen since the beginning of this year.
• At a military base in eastern Mosul, about 260 miles (420 kilometers) north of the capital, a suicide bomber drove a car loaded with explosives into a security checkpoint. Four people were killed, three of them Iraqi soldiers, and nine others wounded, including five soldiers, police said.
• In Samarra, 62 miles (100 kilometers) north of Baghdad, men attacked a police headquarters with guns, hand grenades and rocket-propelled grenades, killing eight police officers and wounding 13 others, police officials in Samarra and Tikrit said.
• In Baiji, about 124 miles (200 kilometers) north of Baghdad, a roadside bomb exploded near a convoy that included a police commander, Col. Ahmed Saleh, killing him and two other officers and wounding another, police said.
The attacks came a day after the U.S. Embassy in Baghdad noted that hundreds of Iraqis, including women and children, have been killed or wounded in recent weeks "by terrorists who pursue their goals through the senseless slaughter of the innocent."
CNN's Tom Watkins contributed to this report.