TIKRIT, Iraq -- Guerrillas fired small arms and rocket-propelled grenades at a U.S. Army Black Hawk helicopter after it came down Saturday in a field near Tikrit, wounding one soldier and causing the craft to explode in flames and spew a column of black smoke, the U.S. military said.

Near Fallujah, three civilians were killed and two wounded when their convoy came under fire. An American engineer and an Iraqi security guard said U.S. troops shot at their vehicles, but the military denied that.

Amid the ongoing violence, U.S military officials prepared for the holy fasting month of Ramadan, which begins in Iraq on Monday. For weeks, chaplains have been training troops to be sensitive to Muslim religious traditions.

In the incident near Fallujah, three SUVs of the European Landmine Solutions, a British-based private contractor, were hit by gunfire, according to an American engineer with the firm, David Rasmussen, who was hospitalized with wounds.

Asked where the shots came from, Rasmussen replied: "from the USA."

The Iraqi security guard traveling with the convoy, Laith Yousef, offered the same account.

"We were the target of an attack by the Americans," Yousef said. "They shot at our car. The translator burned to death in the car. A man with us was killed. He was going to get married next week."

A U.S. command spokesman in Baghdad denied troops fired at the convoy, saying coalition forces went to the secure the area after the attack and evacuated the wounded.

Lt. Col. Charles Hardy, spokesman for the 82nd Airborne Division, which is responsible for the area, said the civilian convoy turned around after a bomb exploded ahead of it, and then was hit by another improvised bomb, rocket-propelled grenades and small-arms fire.

"U.S. forces arrived after the attack and treated the wounded," he said. "This was not initiated by our forces."

The Black Hawk came down at about 4 p.m. in a field near Saddam Hussein's hometown of Tikrit. Both it and Fallujah lie inside the "Sunni Triangle," which sees multiple attacks every day against U.S. forces.