A suicide bomber driving a minibus packed with explosives killed at least 47 people and wounded more than 160 others in the southern Iraqi city of Hillah, police and medical sources have said.
The attacker approached a main checkpoint at a northern entrance to the Shia-majority city on Sunday, and detonated the minibus, a police officer said on condition of anonymity.
At least 50 cars were set ablaze with passengers trapped inside and part of the checkpoint complex was destroyed, the officer said.
It was not immediately clear who was behind the attack.
"I was sitting inside my kiosk when suddenly a horrible blast threw me outside and hurled my groceries up in the air. I saw cars set ablaze with people burning inside," Abu Nawar, owner of a makeshift kiosk made of palm tree leaves near the checkpoint, told Reuters news agency.
Police were using cutting equipment to break inside the burnt vehicles and lift out charred bodies, the police officer said, adding that the death toll was expected to rise.
"When a policeman suspected the minibus, he asked the driver to pull over for a check, but the vehicle exploded," the police officer said.
Iraq has seen a spike in violence since last April, with the death toll climbing to its highest levels since the worst of the country's sectarian bloodletting in 2006-2008.
The UN says 8,868 people were killed in 2013, and more than 1,400 people were killed in January and February of this year.