A wave of bombings and shootings have hit Baghdad and elsewhere in the recent weeks blamed on Sunni insurgents.

US and Iraqi officials speculate that the pinpoint strikes seek to discredit the Shiite-led government after a seven-month political standstill following Parliament elections in March.

Gunmen blocked the car of Col. Mohammed Aziz near his home in Mosul and opened fire with weapons fitted with silencers, police officials said.

Near the southern city of Najaf, meanwhile, a parked motorcycle packed with explosives exploded as a US military patrol passed, security officials said. There were no casualties reported.

The US military did not immediately provide details of the reported attack.

All officials spoke on condition of anonymity because they were not authorized to talk to the media.

In Baghdad, Iraqi officials met with US business envoys as part of the first high-level American trade delegation to Iraq in more than 30 years.

Iraq has been desperate to court foreign investment, but many companies and governments have been cautious because of security worries, corruption and the political limbo after the March elections.

Deputy Prime Minister, Roj Nouri Shawis, tried to assure the delegates that Iraq has made "successes" against insurgents and bureaucratic snags to investment.

The US trade delegation included Boeing Co., General Electric Co. and 12 other companies. The visit is sponsored by the US Commerce Department.