* Iraqi bishop says Islamic State are "thieves, fanatics"
* Pope Francis says Mosul Christians persecuted
* Fleeing family says robbed at checkpoint
By Raheem Salman
BAGHDAD, July 20 (Reuters) - A senior Iraqi bishop urged the world to act on Sunday after Islamic hardliners drove Mosul's Christians from the northern Iraqi city, effectively ending a presence there dating back to Christianity's earliest years.
"The world must act, speak out, consider human rights," Chaldean Catholic Bishop Shlemon Warduni said on Sunday, a day after a deadline expired for Christians in Mosul to submit to the rule of the radical Islamic State or die.
Hundreds of Christian families left the city ahead of the ultimatum, many of them stripped of their possessions as they fled for safety, the remnants of a community which once numbered in the tens of thousands.
"Gunmen lurking like thieves took everything from them - even women's rings, cars, cell phones... because they are fanatics," Warduni told Reuters by telephone from the city of Arbil, 50 miles (80 km) away in the autonomous Kurdish region.
The bishop said the solution to the crisis should be in Iraq's own hands but the state was weak and divided, and Muslim leaders had failed to speak out.
"We haven't heard from clerics from all sects or from the government," he said. "The Christians are sacrificed for Iraq".
This week the Islamic State, leading a Sunni insurgency which took over Mosul on June 10 and now controlling most Sunni Arab provinces in Iraq, gave the city's Christians a choice: convert to Islam, pay a religious tax, or face the sword.
Church leaders said they told the last few families to leave Mosul, where the al Qaeda offshoot has already painted signs on their houses designating them "property of the Islamic State".
Iraqi Prime Minister Nuri al-Maliki condemned the treatment of the Christians and what he described as attacks on churches in Mosul, saying it showed "the extreme criminality and terrorist nature of this group".
He said instructed a government committee which was set up to support displaced people across Iraq to help the Christians who had been made homeless, but did not say when the army might try to win back control of Mosul.
Iraq's security forces, which wilted under the weight of last month's Islamic State-led offensive, have been reinforced by Shi'ite militia fighters and are trying to push back the Sunni militants further south. So far they have failed to take back significant territory from the insurgents.
The Islamic State fighters have also destroyed Shi'ite mosques and Muslim shrines, both of which are considered heretical to their ultra-conservative brand of Sunni Islam.
POPE SAYS CHRISTIANS PERSECUTED
Pope Francis said he was troubled by the Islamic State ultimatum in his weekly public prayers on Sunday.
"I learned with great concern the news that came from the Christian communities in Mosul and other parts of the Middle East, where they have lived since the birth of Christianity and where they have made significant contributions to the good of their societies," he said.
"Today they are persecuted. Our brothers are persecuted. They've been driven away. They must leave their homes without being able to take anything with them."
One Christian who left Mosul last week described how he fled with his family when he learnt of Islamic State deadline.
"We gathered all our belongings and headed for the only exit. There was a checkpoint on the road and they were stopping cars there," 35-year-old Salwan Noel Miskouni said.
When the militants saw they were Christians they demanded gold and money. The family initially said they had none, one of the fighters took their four-year-old son by the hand and threatened to abduct him.
"My sister emptied her entire handbag with our money and gold and her ID. They let the car pass and the child go," Miskouni said.
A few Christian families had stayed on, he said, hiding with Muslim neighbours who gave them shelter. But for now, he saw no possibility of returning with his family.
"If (the Islamic State) leaves we will probably go back but if they stay it's impossible - because they will slaughter us." (Additional reporting by Isabel Coles in Arbil and Steve Scherer in Rome; Editing by Raissa Kasolowsky)