* Kurdish regional interior minister expects long Mosul battle
* Kurdish forces closing in on Mosul
* Signs of revolt against Islamic State
By Samia Nakhoul and Michael Georgy
ERBIL, Oct 22 (Reuters) - Iraqi forces have advanced to 5 km (3 miles) from Mosul in an offensive against Islamic State's last major Iraq stronghold and there are signs of revolt against the group, the interior minister of the Kurdish regional government said on Saturday.
He added, however, that the battle is not expected to end soon.
Karim Sinjari, who is also acting defence minister in the area, also said Islamic State fighters believed to number between 4,000 and 8,000 will put up a fierce fight because of Mosul's symbolic value for the hardline Sunni Jihadis. (Editing by Jeremy Gaunt)