Baghdad, Oct 22 (IANS): US Defence Secretary Ashton Carter arrived here on Saturday on an unannounced visit as Iraqi forces are fighting to defeat the Islamic State militant group from its major stronghold in the country.

Carter will meet Iraqi Prime Minister Haider al-Abadi, other officials and military commanders to discuss the Iraqi offensive against the IS in Mosul, Xinhua news agency reported.

Hundreds of US troops are already in Iraq, serving as trainers and advisers, to help the country win the battle against the IS.

The US-led international coalition has been conducting air raids against IS targets in both Iraq and Syria.

Carter's visit comes as the Iraqi security forces backed by anti-IS coalition are carrying out a major offensive to drive out the IS militants from Mosul.

Al-Abadi, who is also the commander-in-chief of the Iraqi forces, on October 17 announced the beginning of a major offensive to retake Mosul, the country's second largest city.

Mosul, some 400 km from Baghdad, has been under IS control since June 2014, when Iraqi government forces fled the city.