Iraq's PrimeMinister Haider al-Abadi said that the Islamic State group's occupation of northern part of the country and the battle to defeat it has caused more than 100 billion US dollar worth of damage. He was speaking during a visit to Karbala, a city holy to Shiite Muslims, where millions of pilgrims gathered to mark the annual Arbaeen commemoration.<br/><br/>IS had seized around a third of Iraq and parts of Syria in a sweeping 2014 advance.<br/>Iraqi forces yesterday launched an operation to retake the last IS-held towns in Iraq, including the Euphrates valley town of Rawa and nearby villages. Mr Abadi said that the assault also aims to "clean open areas in the desert" of western Iraq.