A suicide car bomber has killed 19 people at a prison gate near Baghdad, Iraqi officials say.
They say at least 22 people were injured in the attack in the town of Taji, some 25km (15 miles) north of the capital.
The casualties reportedly include security guards, prison staff and police officers.
It was not immediately clear if the early morning attack was part of a prison escape attempt.
'Smoke and fire'
The attacker detonated the bomb at about 08:00 local time (05:00 GMT) at the main entrance to the Hout prison, officials say.
The blast happened as many prison employees were on their way to start their shifts at the jail.
"There was smoke and fire all around the place. I saw bodies of four policemen on the ground and scattered flesh," police officer Hisham Ahmed was quoted as saying by the Associated Press news agency.
"Women were among the wounded," he added.
Police had to fire into the air to disperse the crowds of onlookers after the explosion, fearing a second blast.
It was a third major attack in Iraq in the past five days.
On Saturday, at least 15 people died and more than 20 were injured in a series of bomb explosions in and around Baghdad.
Two days earlier, bomb blasts in the southern city of Basra left at least 19 people dead and 65 injured.
Violence in Iraq has declined from its peak in 2006-2007, but regular attacks by militants have raised concerns over whether the planned withdrawal of US troops - due to be completed by the end of this year - will lead to a worsening of the security situation.