Heads up boys, it's the Yanks!

(CNN) -- U.S. forces in Baghdad accidentally shot at the car of the Canadian ambassador to Iraq, John Holmes, but no one was injured, a State Department official said.

It was not immediately clear whether Holmes was inside the vehicle.

"It's an unfortunate incident," the official said of Tuesday's incident. "We are in close contact with the Canadians about the matter."

A Canadian official said the car, which was carrying four people with the Canadian mission in Iraq, was fired on in the capital's heavily fortified Green Zone.

In another incident, Italian authorities said this month they had closed their investigation into the killing of an Italian intelligence officer in Baghdad by U.S. troops in Iraq, the probe's investigative judge said.

The judge, Franco Ionta, would not say whether investigators recommended charges against the U.S. soldier who fired the shots that killed Nicola Calipari and wounded a newly freed Italian hostage, journalist Giuliana Sgrena, in Baghdad in March 2005.

American troops opened fire at the vehicle carrying Calipari, 50, and Sgrena as it approached a checkpoint en route to Baghdad International Airport. A U.S. probe found that the vehicle was traveling about 50 mph, and failed to stop at a checkpoint when ordered to do so.

The Italian investigation concluded that stress and inexperience of the soldiers played a role.

So where does that put the U.S. vs. the world friendly fire incident-ometer?