Iraqi army in Mosul offensive

Reinforcements are due to move into the area in the coming days for what is being called Operation Lion's Roar.

A curfew is already in effect in the city and judges have issued a number of arrest warrants for al-Qaeda leaders.

Over the past year al-Qaeda has lost its foothold in western Iraq and the northern city of Mosul is viewed as its last urban stronghold.

Spent force

A military offensive against Islamists in the city, in the northern province of Nineveh, had long been anticipated, according to the BBC's Clive Myrie, in Baghdad.

The Sunni tribesmen involved in the operation were once allies of al-Qaeda but now back coalition forces.

Prime Minister Nouri al-Maliki has for several weeks been saying that al-Qaeda is an isolated, spent force in Iraq and that he is confident it can be driven out of the country completely.

The operation comes after Iraqi authorities mistakenly announced that the leader of al-Qaeda in Iraq, Abu Ayyub al-Masri, had been captured in Mosul.

US officials denied al-Masri had been captured, saying a man with a similar name had been detained.