Fighters of the Islamic State of Iraq and Syria (ISIS) stand guard at a checkpoint in the northern Iraqi city of Mosul, June 11, 2014.

Iraqi forces launched an operation on Tuesday to drive Islamic State militants out of Tikrit, hometown of executed former dictator Saddam Hussein, officers in the operations room told Reuters.

© Thomson Reuters 2014

They were advancing rapidly from the south but were slowed by landmines, roadside bombs and snipers in the west, said an army major and a police captain.Iraqi and Kurdish forces have been encouraged by the first US air strikes in the country launched against the hardline Sunni insurgents since American troops withdrew in 2011.