KIRKUK, Iraq (AP) -- The body of a Christian health worker turned up in a field two days after he was kidnapped - prompting several more Christian families to pack up and leave their ancient homeland in northern Iraq.

At least 10 Christian families have left Kirkuk in recent weeks, fearing kidnap-for-ransom gangs that have turned their sights on Christians in one of Iraq's most ethnically diverse cities.

The recent violence and abductions has prompted Kirkuk's archbishop to demand government protection against what he has called religious-driven "terrorism."

Attacks are not new against Iraq's small but historically significant Christian community, whose roots stretch back to the early centuries of the faith and include areas mentioned in the Bible.

The departures are just the latest in an ongoing exodus of Christians in Iraq, who have been targets of sectarian violence since the U.S.-led 2003 invasion.

Christians first began leaving Iraq after the 1991 Gulf War, during the economic sanctions and repression under Saddam Hussein, who pushed more Islamist policies. But the trickle turned to a flood after Saddam was toppled and the violence escalated.

Thousands of Christians have fled northern Mosul to join relatives abroad or as part of the more than 2.7 million people who have been displaced since the war began.

But the violence in Kirkuk resonates with special concern for Iraqi officials. The city - the hub of Iraq's northern oil fields - is at the heart of a political and cultural struggle between Kurds, Arabs and Turkomen. The rivalries are so bitter that Kirkuk was excluded from provincial elections earlier this year and there are worries about increased tensions before balloting for parliament in January.

Kirkuk's smaller minorities, such as Chaldean and Assyrian Christians, increasingly worry about being caught in the middle.

"We think there is a political nature to these kidnappings, which is meant to force us to leave Iraq," said Kirkuk's Chaldean Archbishop Lewis Sako on Monday.

A day earlier, the body of Imad Elia, a 45-year-old employee at Kirkuk's health directorate, was found dumped in a field south of the city, about 180 miles (290 kilometers) north of Baghdad. He was shot in the chest and authorities believe the captors kept shooting into his body after he was dead.

Elia was kidnapped two days before, but his family was unable to pay the ransom demands, Sako said.

Last month, a well-known Christian pediatrician was kidnapped in Kirkuk, but released after his family paid the kidnappers $100,000.

There have been no clear clues on the background of the gangs. But Sako pointed the finger at Islamic extremists whom he claims want to drive out Kirkuk's remaining 10,000 Christians.

"These acts are really malicious. Extremists are using religion as a pretext to target Christians," he said. "We call upon the government to provide necessary protection to Christians because these acts meant to frighten Christians out of the country."

Last year, gunmen stormed two Christian homes in Kirkuk in separate attacks, killing a total of three people. In his sermon to mourners, Sako said the slain Christians were victims of "terrorism."

Rand Anwar, a Christian journalist in Kirkuk, also accused government security forces of failing to protect Christians.

"Police failed to catch a single criminal involved in the crimes committed against Christians in the past years. Not a single one ... And now these kidnappings. Police do not protect us nor do they care about our problems," Anwar said.

But Kirkuk police Maj. Gen. Jamal Tahir called the charges "baseless."

"There is no flight of Christians from Kirkuk because of violence. Christians normally leave willingly to other areas or other countries to live in better conditions, but not because of any escalation of violence especially in Kirkuk's Christian neighborhoods," Tahir said.

The last official Iraqi census in 1987 found 1.4 million Christians in the country. Now, according to the 2008 U.S. State Department report on International Religious Freedom, that number has dropped to between 550,000 and 800,000.

Some estimate the number is even lower: only 400,000, according to the German Catholic relief organization Kirche in Not.

By Yahya Barzanji