At least 45 people have been killed in a series of co-ordinated attacks across Iraq, officials say.
Two car bombs in the predominantly Shia city of Kerbala killed at least 13 people.
Another car bomb near police headquarters in the northern city of Kirkuk killed another 13 people, most of them officers, police said.
The attacks come ahead of next week's Arab League summit to be held in the capital, Baghdad.
Security forces in Iraq have been placed on high alert in the run-up.
The attacks also coincide with the ninth anniversary of the beginning of the US-led invasion of Iraq.
The summit is seen as the country's return to the regional stage following the withdrawal of US troops in December.
The BBC's correspondent in Iraq, Rami Ruhayem, says such coordinated campaigns have become a recurring nightmare in the country, and show that the security forces remain fatally flawed.
Parliament speaker Osama al-Nujaifi said the "brutal, criminal" attacks were part of efforts by al-Qaeda to "derail the Arab summit, and keep Iraq feeling the effects of violence and destruction".
An MP for the Shia Dawa party, Haider al-Abadi, said the perpetrators wanted to "show that democracy in Iraq doesn't work".
The UN secretary-general's special envoy to Iraq, Martin Kobler, described the attacks as "atrocious", and called for those responsible to be identified and brought to justice.
In Baghdad, two separate car bomb attacks - one of them opposite the foreign ministry building - killed seven people.
Earlier in the day, three people died in an attack on a Baghdad church, AFP reports.
Numerous attacks were reported elsewhere around the country, including Hillah, Mahmudiya and Latifiya to the south of Baghdad, as well as in Ramadi, Baiji, Daquq, al-Dhuluiya and Samarra, in the mainly Sunni area to the west and north of the capital.