Car bombs explode in Baghdad and Kirkuk, and police checkpoints come under attack overnight
At least 21 people have died in a dozen blasts and a series of shootings in cities and towns across Iraq.
No one has claimed responsibility for latest in a series of attacks since US troops left in December.
In Baghdad on Thursday, a car bomb killed six civilians and wounded 28 in the mainly Shia district of Husainiya. Four car bombs exploded in Kirkuk, 150 miles north of Baghdad, killing two and wounding 18.
Overnight attacks on police checkpoints in the cities of Baquba and Falluja killed six police officers and wounded 13 and there were car bombs, shootings and sticky bombs – often explosives attached to vehicles with a magnet – in other towns. Nine were wounded by a car bomb in Taji, just to the north of Baghdad.
Al-Qaida's local wing, the Islamic State of Iraq, said it carried out attacks in June and July as part of a renewed offensive. It has been reinvigorated by the inflow of fighters and cash into neighbouring Syria, providing a morale boost and some extra arms and cash, security experts say. Iraqi insurgents are vowing to retake territory lost during a long war with American troops.
Security has been increased before the end of the Muslim holy fasting month of Ramadan next week, a period when analysts believe insurgents may attempt a major attack.