BAGHDAD (AFP) - A car bomb targeted a church in the Iraqi capital on Wednesday as worshippers left after a Christmas service, killing at least 17 people, most of them Christians, security officials said.

The blast in the Dura area of south Baghdad also wounded more than 34 people, the sources said.

"The attack targeted the church, and most of the martyrs are Christians," a police colonel told AFP. "The attack on St John church occurred when worshippers were leaving the church" after a service.

There was no immediate claim of responsibility for the attack.

"Attacks distort the image of Islam and religion, if they are carrying them out in the name of religion," Monsignor Pios Cacha of Baghdad's St Joseph church told AFP.

"The church is a place of love and peace, and not for wars," Monsignor Cacha said.

Earlier in the year, Monsignor Cacha had said that "maybe we will follow in the steps of our Jewish brothers," referring to a once-thriving community that is now practically non-existent.

Iraq has seen its Christian population sharply decline in the years since 2003.

The 2003 US-led invasion of Iraq ended dictator Saddam Hussein's disastrous rule, but also turned the country into a battleground between insurgents and foreign troops, unleashing a wave of bombings and killings by militants in which Christians were not only caught in the crossfire, but targeted themselves.

The bloodiest single attack on the community happened on Oct 31, 2010, when militants killed 44 worshippers and two priests in Baghdad's Our Lady of Salvation church.

Estimates of the number of Christians living in Iraq before 2003 vary from more than one million to around 1.5 million. But now they are estimated at fewer than 500,000.

Violence in Iraq has surged this year to levels not seen since 2008, when the country ws just emerging from a brutal period of sectarian unrest.

More than 6,650 people have been killed in Iraq since the beginning of 2013, according to AFP figures based on security and medical sources.