At least 14 people have been killed in a series of bomb blasts in the northern Iraqi city of Kirkuk, police say.
Eight bombs went off in various parts of the city within half an hour. More than 30 people were hurt, police said.
The oil-rich, predominately Kurdish city lies about 290km (180 miles) north of the capital, Baghdad, and has seen many attacks in recent years.
Earlier, police in Baghdad said a bomb had exploded near a Shia mosque, killing at least five people.
The attack in Baghdad happened in the Shorja district, which has been a frequent target of suspected Sunni Arab insurgents.
A Kirkuk police commander, Brigadier Tarhan, told the BBC that four car bombs and four roadside bombs had been detonated across the city between 1330 and 1400 local time (1030-1100 GMT).
Several police officers are said to have been killed.
Kirkuk has suffered a series of car bomb attacks in recent months
In recent months, violent attacks have been on the increase in Kirkuk. Kurds, Arabs and Turkomens all claim ownership of the city and the oil-rich lands around it.
The BBC's Jim Muir in Irbil in northern Iraq says many of the previous bomb attacks in Kirkuk have been blamed on Sunni insurgents, as part of their wider campaign of violence.
But tensions have been rising in the city, he says, with the approach of deadlines for a census and a referendum on whether its inhabitants want the province to be joined with the three others which make up Iraqi Kurdistan.
Under the new Iraqi constitution, that process is supposed to be completed by the end of the year.
But while the Kurds want to push it ahead, our correspondent says, the Arab and Turkomen minorities are strongly opposed, as is neighbouring Turkey.
The latest violence came as a new survey painted a pessimistic picture of Iraqis' confidence in their own government and in coalition forces, four years on from the US-led invasion.
Only 18% of Iraqis have confidence in US and coalition troops, while opinion is almost evenly split on whether to have confidence in Iraq's government, the BBC/ABC News poll found.
About 86% of the more than 2,000 people questioned expressed concern about someone in their household being a victim of violence.