At least 16 Iraqis were killed on Sunday in Iraq in a series of attacks which were followed by the bombings by churches in Baghdad and Kirkuk.
Car bombs exploded in a co-ordinated spree of attacks outside the Vatican mission and at least four churches in Baghdad and the northern city of Kirkuk within 20 minutes, killing at least three Iraqis and wounding nine.
Police Colonel Birhan Taha said three civilians were killed and one wounded in the attack on the Church of the Virgin in Kirkuk at 4.30pm on Sunday.
Fifteen minutes earlier, a car bomb exploded outside an Orthodox church, wounding six civilians.
Both cars were detonated by remote control, Taha said.
In Baghdad, three car bombs exploded outside two churches and the nearby Vatican embassy building in eastern Baghdad within 20 minutes.
Major Qusai Ibrahim said the first detonated at 4.10pm outside The Disciples of St Peter and Paul Orthodox church in the suburb of Sinaa, wounding two people.
Lieutenant Ali Mitaab said another bomb-packed vehicle exploded at 4.30pm outside an Anglican church in eastern Baghdad's Nidhal area, causing no casualties.
Police Major Abbas Mohammed said that at about the same time, a fifth car bomb exploded about 50m from the Vatican mission's building. Nobody was reported hurt.
Monsignor Fernando Filoni, the papal nuncio in Baghdad, said he was too busy to talk when contacted by the AP, but a woman who answered the phone at the nuncio's office said a car exploded outside the embassy at 4.30pm.
In August, a wave of bomb attacks at churches killed 11 people.
Iraq's Christian community, which makes up about 3% of the population, has become increasingly nervous over violence and attacks on Christian-owned alcohol shops.
Also on Sunday, a policeman was killed and another nine people, including three policemen, injured in two separate attacks in Baquba.
In anther incident, Iraqi police found six bodies of Iraqis in Khan al-Rubaa on the road between the Iraqi city of Najaf and Karbala.
The bodies had their hands tied and had been shot in the head.
The US army said two US soldiers on Saturday were killed when an explosive device hit their patrol in Baghdad, bringing the US soldier death toll to 2243 since the war on Iraq started.