Insurgents bent on wrecking Sunday’s election in Iraq killed 10 Iraqis and two US troops on Friday but the government said it had caught three al-Qaeda lieutenants and insisted guerrillas were on the defensive.

The government imposed extraordinary security restrictions to try to safeguard the polls. Land borders were closed and travel between provinces was banned. An extended curfew was imposed in most cities from 7pm to 6am (1600-0300 GMT).