Iraqi army's elite force pauses advance near Mosul

On the ninth day of the offensive on Mosul, government forces and allied Kurdish Peshmerga fighters are still fighting their way towards the outer limits of the northern city, in the early stages of an assault which could become the biggest military operation in Iraq in over a decade.

The first force to get near to Mosul, advancing to within two kilometers (just over a mile) of Iraq's second largest city, was the elite U.S.-trained Counter Terrorism Service (CTS).

CTS troops have moved in from the east, dislodging Islamic State from a Christian region that has been empty of residents since the ultra-hardline Sunni militants took it over in 2014.

The combat ahead is likely to be more difficult and deadly because of the presence of civilians. Some 1.5 million residents remain in the city and worst-case forecasts see up to a million being uprooted, according to the United Nations.

U.N. aid agencies said the fighting has so far forced about 9,000 to flee their homes. But Lise Grande, the UN humanitarian coordinator for Iraq, told Reuters that the United Nations expects a mass exodus from Mosul, perhaps within the next few days.

In the worst case scenario, Grande said it was also possible that Islamic State fighters who have controlled Mosul for more than two years could resort to "rudimentary chemical weapons" to hold back the impending assault.

U.N. human rights spokesman Rupert Colville said Islamic State fighters have reportedly killed scores of people around Mosul in the last week.

Colville said that security forces discovered the bodies of 70 civilians in houses in Tuloul Naser village south of Mosul on October 22.

Islamic State also reportedly killed 50 former police officers outside Mosul on October 23, he said.