Kurdish Peshmerga forces backed by US-led coalition airstrikes have launched a fresh attack on Islamic State militants in northern Iraq, as part of a plan to close in on their de facto capital Mosul, a Kurdish official said.
The offensive began in the early hours of Sunday after heavy shelling and several airstrikes, a Reuters correspondent reported from Wardak, 30km southeast of Mosul, where some of the Peshmerga forces are deployed.
Clouds of black smoke could be seen at a distance, possibly tyres or other items set on fire by the militants to obstruct the planes' visibility.
The Iraqi army and the Peshmerga forces of the Kurdish self-rule region are gradually taking up positions around Mosul, 400km north of Baghdad, from whose Grand Mosque in 2014 Islamic State leader Abu Bakr al-Baghdadi declared a caliphate spanning regions of Iraq and Syria.
Mosul is the largest urban centre under the militants' control, with a pre-war population of nearly two million.
Its fall would mark their effective defeat in Iraq, according to Iraqi Prime Minister Haider al-Abadi, who has said he aims to retake the city this year.
The operation that started Sunday is part of the "shaping operations" to prepare for an offensive on the city itself, said a Kurdish official who declined to be identified.
The Iraqi army is trying to advance from the south. In July it captured the Qayyara airfield, 60km south of Mosul, which will serve as the main staging post for the expected offensive on the city.