A car bomb has ripped through a funeral tent in a mainly Shia Muslim area of Baghdad, killing 48 people.
Officials say that another 78 people were wounded in the mid-afternoon blast in the north-western Shula district.
Angry mourners attacked police who rushed to the scene, accusing them of failing to provide protection.
The funeral attack comes after a series of bombings killed dozens of Shia pilgrims during their annual pilgrimage to the holy city of Karbala last week.
A spate of bombings in the past month against pilgrims, police recruits and security forces across Iraq has killed more than 170 people.
The recent rise in violence comes as the US military prepares to withdraw from the country at the end of the year.
It poses a major challenge to Iraqi Prime Minister Nouri al-Maliki and his fragile coalition government, formed only last month.
The car that exploded at about 1400 local time (1100 GMT) on Thursday was parked near the funeral in the Shula area.
Ali Kamil, a 22-year-old college student who lives nearby, told the AP news agency that he rushed to the scene and saw a fire still raging. Several cars in the area were damaged, he said.
He said young men were throwing stones at the Iraqi security forces, angry that they had failed to protect them.
Other witnesses said police fired into the air to disperse the angry crowd, but then came under attack from gunmen and returned fire. It is unclear if anyone was hurt in the shooting.
Finally, the military was sent in to restore order, they said.
In other parts of the capital on Thursday, five people were killed and 21 wounded by roadside bomb attacks, while another bomb planted inside a minibus killed two people and wounded seven in the Jihad neighbourhood.
Violence has declined sharply in Iraq since the height of the sectarian killings of 2006-2007, but near daily attacks continue.