At least 25 people were killed in car bomb and mortar attacks in mainly Shia Muslim districts of Baghdad on Tuesday, Iraqi police and medical sources said.
There was no immediate claim of responsibility for the attacks but Islamic State, ultra-radical Sunni Muslim militants who seized swathes of northern Iraq in June, claimed several suicide bombings in the capital earlier this year.
Two car bombs exploded in busy streets in the al-Horreyya district, killing 20 people and wounding 35, according to the police and medical sources. There was also a mortar attack in the Sab al-Bour neighbourhood of northern Baghdad that killed five people and wounded 15.
Baghdad has witnessed relatively fewer attacks compared to the violence in other areas hit by Islamic State's offensive, though bombs still hit the capital on a fairly regular basis.
There were also several small-scale attacks in predominantly Shi'ite areas across the country. In the southern oil hub of Basra, a parked car bomb exploded in a parking lot, setting ablaze five cars but causing no casualties, police said.
In the town of Kifil, near the Shi'ite holy city of Najaf, at least one person was killed and three wounded by a car bomb. And in Kerbala, a car bomb blast on a busy street wounded at least seven people and torched a police car, police said.
Video: RAF carrys out first attacks on Isis
In the Kurdish-controlled town of Khanaqin, 140 km (100 miles) northeast of Baghdad, at least four Kurdish security members were killed and 12 wounded in a bomb attack on their patrol, police and medics said.
U.S.-led forces started bombing Islamic State targets in Iraq in August and Washington expanded the campaign to Syria last week in an effort to defeat the well-armed insurgents who have swept through Sunni areas of both Iraq and Syria.
Washington hopes the air strikes, conducted with help from European allies in Iraq and Arab air forces in Syria, will allow government and Kurdish forces in Iraq, and moderate Sunnis in Syria, to recapture territory.