Iraq violence: Wave of deadly car bombs targets Shias
A wave of car bombs has killed at least 51 people in mostly Shia areas of the Iraqi capital, Baghdad, and in other cities around the country.
More than 200 people were wounded in the attacks, officials said.
More than 2,500 Iraqis have died in attacks since April, the UN says - with violence at its highest since 2008.
The spike comes amid heightened Shia-Sunni tensions. Sunnis say they are being marginalised by Prime Minister Nouri Maliki's Shia-led government.
The interior minister said in a statement that the scale of the attacks suggested that militant groups had infiltrated the "social fabric of Iraq".
The statement added that it would not be possible for security forces to stop the violence without active co-operation from citizens.
The government is still reeling from a sophisticated jailbreak just over a week ago, when hundreds of prisoners - many of them sentenced to death for involvement in such violence - managed to escape.
The failure of the authorities to prevent the jailbreak and Monday's attacks is opening fissures within the governing coalition and between ministers themselves.
After the jailbreak, there were arguments over whether the blame should fall on the justice ministry or the interior ministry, and Prime Minister Nouri al-Maliki had to sack a number of security officials. Monday's attacks are likely to increase popular anger at the government's failures.
The Baghdad bombs, hidden in parked cars, hit markets and car parks in several areas of the city, police say.
The deadliest was said to have hit the eastern Shia district of Sadr City, report say.
A man says he saw vehicles arriving to park shortly before a blast happened in the district of Habibiya, in southern Baghdad.
"We were standing here when a a pick-up truck drove in here and parked there. There were two others cars parking there. Minutes later the car went off," he told the Associated Press news agency.
One bomb also exploded in Mahmudiya to the south of the capital, killing at least two people.
In the city of Kut, south-east of the capital, at least seven people were killed when two car bombs blew up.
There are also reports of a car bomb going off in Basra, the second city.
This could be the bloodiest month in Iraq for years, says BBC Arabic's Haddad Salih in Baghdad, with the number of attacks escalating since the beginning of the month of Ramadan earlier this month.
Although the violence is less deadly than that seen during the heights of the insurgency in 2006 and 2007, it is the most widespread since the US military withdrawal in 2011. More than 700 people have been killed in July alone.