At least 12 people were killed on Friday in bombings across Iraq, where Sunni Islamist insurgents have been regrouping and gaining momentum in recent months.
No group immediately claimed responsibility for any of Friday's attacks, but al Qaeda's Iraqi affiliate, which was forced underground in 2006-07, has reemerged this year, invigorated by civil war in Syria and Sunni resentment at home.
In the deadliest attack, eight people were killed when a car bomb exploded in the centre of the northern city of Mosul, where Sunni Islamist and other insurgents have a strong presence, witnesses said.
In western Baghdad, two roadside bombs went off near a Sunni mosque as worshippers were leaving following Friday prayers, killing four people, medics and police sources said.
A woman was killed when unidentified gunmen opened fire on a bus carrying Shi'ite pilgrims to a shrine in Balad, north of Baghdad.
Violence in Iraq began to ease from a peak in 2006-07, but is now rising again, with more than 7,000 civilians killed so far this year, according to monitoring group Iraq Body Count.
Iraqi officials blame the bloodshed on al Qaeda and the civil war in neighbouring Syria, which has drawn hardline Sunni Islamists from across the region and beyond into battle against President Bashar al-Assad, who is an ally of Shi'ite Iran.
Al Qaeda's Iraqi wing earlier this year joined forces with its Syrian counterpart to form the Islamic State in Iraq and the Levant, which has claimed responsibility for attacks on both sides of the border.
Critics of Prime Minister Nuri al-Maliki say his Shi'ite-led government's treatment of minority Sunnis has fuelled the Sunni resentment that al Qaeda is now exploiting.