U.S. soldiers shot into a crowd in a Baghdad (search) slum Wednesday, killing one civilian and wounding four, after being fired on with a rocket-propelled grenade, the military said.

The exchange broke out after about 3,000 demonstrators gathered near a telecommunications tower in Sadr City (search), where they said American forces in a helicopter tried to tear down an Islamic banner.

U.S. military spokesman Sgt. Danny Martin said it appeared rotor wash from a helicopter blew down the banner.

However, amateur video footage obtained by Associated Press Television News showed a Black Hawk helicopter (search) hovering about three feet from the top of the tower and apparently trying to tear down the banner. The footage showed U.S. Humvees driving by and the crowd throwing stones at them. Heavy gunfire broke out and the demonstrators hit the ground.

Martin said soldiers from the 1st Armored Division opened fire after stones, gunfire and one rocket-propelled grenade were directed at them.

One civilian was killed and four were wounded, he said. He said no soldiers were hit.

Sadr City, formerly known as Saddam City, is a Shiite Muslim stronghold in the otherwise Sunni Muslim-dominated capital.