VATICAN CITY (AP) -- A Catholic archbishop kidnapped in Iraq has been freed, the Vatican said Tuesday.

The Pope, who had prayed for the bishop's release, was informed immediately of the release, said papal spokesman Joaquin Navarro-Valls. "He changed his prayer to one of thanks," he said.

A ransom of $200,000 US initially had been demanded but the bishop was released without the payment of any money, the Vatican said.

Kidnapped on Monday was Basile Georges Casmoussa, 66, of the Syrian Catholic Church, one of the branches of the Roman Catholic Church.

The Vatican had branded the kidnapping a "despicable terrorist act" and demanded his immediate release.

A priest in Iraq said on condition of anonymity that the archbishop was walking in front of the Al-Bishara church in Mosul's eastern neighbourhood of Muhandeseen when gunmen forced him into a car and drove away.

Mosul, in Iraq's north, has been a hotspot for the violent insurgency in recent months.

The reason for the kidnapping was unclear but Christians - tens of thousands of whom live in and around Mosul - have been subjected to attacks in the past.

Christians make up just three per cent of Iraq's 26 million people. The major Christian groups in Iraq include Chaldean-Assyrians and Armenians. There are small numbers of Roman Catholics.

Officials estimate that as many as 15,000 Iraqi Christians have left the country since August, when four churches in Baghdad and one in Mosul were attacked in a co-ordinated series of car bombings. The attacks killed 12 people and injured 61 others.

Another church was bombed in Baghdad in September.

However, Navarro-Valls said the Vatican didn't view the kidnapping as an anti-Christian act but part of the general climate of violence in Iraq. He said the archbishop was well-loved in the community.