A suicide bomber has killed at least 26 people in an attack on a cafe in a town north-east of Baghdad, police say.
The attacker is reported to have walked into the cafe in the town of Balad Ruz and then detonated the device.
At least 29 other people were also injured in the incident, a police spokesman told the AFP news agency.
In a separate development, three US troops were killed by a roadside bomb attack in the capital, Baghdad, the US military said in a statement.
The soldiers were hit as they were patrolling a well-used route in the city, checking it for hidden explosives, the statement said.
A fourth member of the patrol was injured in the incident.
Balad Ruz is approximately 70km (45 miles) north-east of Baghdad. The part of the town where the bomb attack occurred is described as being populated by members of the region's Shia Kurd minority.
Earlier on Wednesday, at least nine people were killed as Shia pilgrims made their way to the holy city of Karbala.
Seven policemen deployed to protect pilgrims were killed by a car bomb in Doura in southern Baghdad. One pilgrim also died.
In central Baghdad, one person died when gunmen opened fire on pilgrims.
It follows a double suicide bomb attack in the central Iraqi town of Hilla on Tuesday in which at least 90 Shia pilgrims were killed and more than 150 wounded.
Two bombers wearing explosive vests blew themselves up in a large crowd of pilgrims heading to the city of Karbala for religious ceremonies marking Arbaeen - the end of 40 days of mourning for Imam Hussein, a grandson of the Prophet Mohamed who was killed in the year 681.
Iraq has seen a sharp rise in violence between Sunni and Shia Muslims since an attack on a key Shia shrine in Samarra just over a year ago.
Baghdad has been at the centre of a three-week-old US-Iraqi security push, and US military commanders have been warning that militants may focus their efforts on launching attacks outside the capital.