At least four people have been injured after a bomb exploded outside the entrance of a Catholic church in the centre of the Iraqi capital, Baghdad.
The blast outside the Sacred Heart church in the Karrada district broke its windows and sent shrapnel flying.
The attack took place after worshippers at the Easter Sunday service had left.
Iraqi Christians have been the victims of a spate of attacks, including one on a Syrian Catholic cathedral in Baghdad last year that left 53 people dead.
There were once about 1.5 million Christians in Iraq, but more than two-thirds are believed to have fled since the US-led invasion in 2003.
Hundreds of families have also moved to the northern Kurdish region.
'Full of fear'
The victims of Sunday's bombing were two policemen and two civilian bystanders, security officials said.
But one official and a TV cameraman for the Reuters news agency said four policemen and three bystanders were receiving treatment in hospital.
One of the injured policemen, Hassan Dalli, said: "We had just reached the scene to distribute food to the policemen there when the bomb blew up."
There had been no specific threats issued before the attack, but security was nevertheless stepped up on Easter Sunday outside churches in the capital and two northern provinces where many Christians live.
"Our life in Iraq is full of fear," Father Hanna Saad Sirop told worshippers at St Joseph's Chaldean church in Baghdad.
"But we have to live in faith and trust... We have to trust almighty God."
In other violence on Sunday, an army captain was killed by a "sticky bomb" attached to a vehicle in the northern city of Kirkuk, police said.