Iraq forces 'face tough resistance' entering IS-held Mosul

Soldiers from the Counter-Terrorism Service battled their way into the eastern neighbourhood of al-Karama where they were met with bombs and heavy gunfire from IS militants, senior CTS officer Muntathar Salem said.

An AFP reporter posted with the CTS in a cemetery at the eastern entrance to the city saw bulldozers and other armoured vehicles move into al-Karama.

The gunfire was almost uninterrupted and reports from the front crackling into CTS radios said IS had set up barriers and laid bombs along the streets to slow the advance.

Airstrikes by the US-led coalition have intensified over the past two days to prepare for the advance, the first significant incursion into Mosul since IS overran the city in June 2014.

Both the CTS and army units deployed further south had crossed the municipal boundary earlier this week but they held back from entering the built-up area.

An estimated 3,000 to 5,000 IS fighters are scattered across the sprawling city, Iraq's second largest, where a million-plus civilians are believed to be trapped.