A major operation is underway in western Iraq to flush out suspected al-Qaeda fighters. Around 3,500 US and Iraqi troops have launched Operation Steel Curtain, one of the biggest in a series of offensives in the vast Sunni Arab province of Anbar, near the Syrian border.It has been a flashpoint of the insurgency against the US-led coalition. The military says al-Qaeda has taken advantage of the country’s porous frontiers to smuggle militants, money and foreign combatants into Iraq. The objective, it says, is to destroy guerrillas who are accused of intimidating locals who collaborate with Iraqi or US authorities. Turnout in Anbar was low for a constitutional referendum in October and it is thought militants, if left unchecked, will keep voters at home in next month’s election. However, the operation is fuelling sectarian resentment, with Sunni leaders accusing the military of killing civilians.