At least 25 people were killed and 100 were wounded in a double suicide bombing in the northern Iraqi city of Tal Afar on Friday, an Interior Ministry official said.
A suicide car bomber detonated explosives at a stadium where people had gathered to watch a football match Friday evening. Moments later, a second bomber struck the stadium on foot.
Tal Afar is an ethnically mixed city about 420 kilometers (260 miles) northwest of Baghdad.
Later on Friday, at least four Iraqis were killed and eight others wounded when a roadside bomb detonated near a park in the predominantly Sunni district of Adhamiya in northern Baghdad.
The stadium attack followed a spate of violence across Iraq on Monday that claimed 85 lives and injured nearly 300, making it the nation's deadliest day so far this year.
Attacks were launched in six provinces, including Basra, Wasit and Babil - which tend to be less violent than others - in violence reminiscent of what was typical during the height of the sectarian war.
The violence comes at a critical time in Iraq, as the country is struggling to form a government after contentious national elections, a process that Western officials have described as "lagging."
No one has claimed responsibility for Friday's attacks, but such coordinated assaults bear the hallmarks of al Qaeda in Iraq, which is known to take advantage of political fissures to carry out attacks to create turmoil.
- CNN's Jomana Karadsheh contributed to this report.