BAGHDAD – A suicide attacker in an explosives-rigged car bombed U.S. and Iraqi forces on joint patrol Friday, killing two Americans and at least three Iraqis.

The bomber struck the convoy of Humvees and Stryker vehicles in the town of Jalula, about 80 miles northeast of Baghdad, not far from the Iranian border, according to Iraqi officials. The U.S. military said another six Americans were wounded in the attack.

Although U.S. forces have largely pulled back from urban areas as Iraqis take responsibility for securing their country, Friday’s attack illustrates the risks that remain for American troops here.

Names of the casualties were not released, pending notification of family members. The United States said three Iraqis, including one police officer, were killed, and about 22 were wounded in the blast.

It was the deadliest reported attack on U.S. troops since April 7, when two soldiers were killed by a roadside bomb in Mosul.

A man who was watching the patrol from his doorway when the bomber struck said troops were searching for weapons after a dispute among residents armed with hand grenades and firearms the previous day.

The man, who gave his name as Abu Kowyan, said the assailant attacked from a nearby alley, ramming his car into the patrol as troops were getting out of their vehicles.

He said he counted about seven or eight American soldiers lying on the ground after the blast. The fiery explosion shattered windows in his house 20 yards away.

Iraqi police, hospital and local officials said the blast killed six Iraqis, including one policeman, and wounded 22 others. Conflicting casualty tolls are common in the confusion after an attack.

Jalula is located in a corner of Diyala province populated by Kurds and Sunni Arabs, and has been the site of previous attacks. In March last year, a suicide bomber struck a Kurdish funeral in the town, killing 27.

The number of Americans dying in Iraq has dropped sharply, in part because of reduced troop levels as American combat forces prepare to leave by the end of August. But attacks continue.

The Jalula bombing was one of two deadly attacks in Iraq on Friday. A bomb hidden in a pile of trash exploded at a market in southern Baghdad, killing three people. The explosion, in the capital’s Dora neighborhood, wounded 10 others.