BAGHDAD, Aug 28 (Reuters) - At least nine Iraqi soldiers including a colonel were killed on Tuesday after insurgents fired rockets at an army convoy north of Baghdad and gunmen battled troops at checkpoints in a wave of attacks on security forces.
Iraq's insurgency has ebbed since the height of the war four years ago, but militants tied to al Qaeda and other Sunni Muslim Islamists are hitting Shi'ites and security forces in an attempt to undermine the country's Shi'ite-led government.
Military helicopters opened fire on dozens of gunmen attacking checkpoints along a main route north of Baghdad, police and army officials said.
"Dozens of gunmen attacked army and police checkpoints, and army helicopters opened fire with machine guns at their locations," one police officer, Saif Ali, said by telephone, near the site of the one of the attacks.
Two other soldiers were killed by gunmen using silenced weapons in the north of the capital, police said.
Gunmen in four vehicles assaulted the colonel's convoy outside the capital, before hitting his car with a rocket-propelled grenade and heavy machine gun fire, killing him and six other soldiers, officials said.
Eight months after the last U.S. troops left, the Iraqi al Qaeda affiliate has vowed to revive attacks against Iraq's Shi'ites in an attempt to fuel the broad sectarian violence that drove the country to edge of civil war four years ago.
Insurgents also often target local police and army to show authorities are incapable of protecting Iraqis, nine years after the fall of Sunni dictator Saddam Hussein.
While violence has dropped sharply, insurgents carry out at least one major attack a month. Security experts say Sunni Iraqi insurgents have been emboldened by the Sunni-led revolution in neighbouring Syria. (Reporting by Ahmed Rasheed, Kareem Raheem and Gazwan Hassan; Writing by Patrick Markey; Editing by Andrew Heavens)