IRBIL, Iraq — Thousands of Iraqi Christians flocked back to their homes in the north on Sunday, days after they fled villages under attack by Sunni Muslim extremists.

Hundreds of people packed into cars, jeeps and buses were crossing a checkpoint on their way back after ruling Kurdish forces told them it was safe to return.

The cluster of villages is in an area known as Hamdaniya, some 45 miles (75 kilometers) inside the border of the largely autonomous Kurdish-held region. It came under attack Wednesday by Sunni insurgents near the northern city of Mosul, led by the al-Qaida inspired Islamic State in Iraq and the Levant.

The Sunni insurgents fired mortar shells on the outskirts of the village, panicking thousands of residents who thought extremists would overrun their villages.

Amer Bahman, 52, said Christians began returning over the weekend.

"They said there was no fighting left," said Bahman, a Chaldean Christian, by telephone from Hamdaniya.

He had taken shelter in an encampment for displaced Iraqis near the northern Kurdish city of Irbil. On Saturday, his children Andy and Amanda, grubby from the camp's pervasive dust, chatted gregariously in the ancient Chaldean language.

By Sunday afternoon, a sports center in Erbil that had sheltered hundreds of displaced was empty. Tents once-filled with the displaced near a television station flapped abandoned in the hot summer wind.

"We try to encourage them to go back, be strong and stick to their land," said Ignatius Joseph III, patriarch of the Syriac Catholic church, as displaced Iraqis prepared to leave their temporary shelters. "We think that our survival here is at stake and is very threatened," he said.

Christians in Iraq have warned that their ancient community's survival is in danger since the Sunni insurgency seized swathes of northern Iraq, including their ancient heartland of Ninevah and Mosul.

Community leaders estimate there were some 1.5 million Christians in Iraq before the U.S.-led invasion in 2003. Since then, the country's general violence and attacks targeting Christians have caused over half the community to flee.

Within Iraq, thousands of Christians have resettled in Kurdish-ruled northern areas, seen as safer and more prosperous than the rest of Iraq.

Iraqi Christians belong to denominations such as Chaldeans and Syriacs, which emerged in the first days of Christianity. Many speak languages similar to those spoken at the time of Christ.