An American soldier suspected of leaking video footage of a US Apache helicopter strike in Iraq in which around a dozen people were gunned down in broad daylight has been charged, the army said on Tuesday.

The video of the attack in a Baghdad street on July 12, 2007 was posted on the Internet, causing international outcry over an action in which civilians were killed after being wrongly identified as insurgents.

It also provoked anger and renewed demands for compensation from the victims families, as well as acute embarrassment at the Pentagon and the White House.

Private First Class Bradley E. Manning, currently being held in a military jail in Kuwait in connection with the attack, faces two charges of misconduct, the US army in Baghdad said in a statement.

WikiLeaks, a whistleblowing website, released in April the video that showed several people, including two Reuters news agency employees, being killed.

As well as releasing the video, Manning, 22, is accused of illegally downloading more than 150,000 diplomatic cables, 50 of which he is alleged to have transmitted unlawfully to the danger of US national security.

The first charge against Manning is for violating army regulations by "transferring classified data onto his personal computer and adding unauthorised software to a classified computer system," the statement said.

The second charge says the soldier, who has been in custody since May 29, according to his charge sheet, is also accused of "communicating, transmitting and delivering national defence information to an unauthorised source."

WikiLeaks at the time said it obtained the video "from a number of military whistleblowers" and decrypted it. It posted the video at collateralmurder.org.

The gun camera footage of the attack included audio conversations between Apache pilots and controllers in which they identified the men in Baghdad as armed insurgents and asked for permission to open fire.

Two of the men were later identified as Reuters employees Nameer Nuraddin Hussein, a 22-year-old photographer, and Saeed Chmagh, 44, a driver.

Their families, who said they have until now received no compensation for the incident, have demanded that the Americans responsible should stand trial.

After the leaked and graphic footage was released the White House described the incident as "tragic," insisting that US forces in war zones take pains to avoid civilian casualties.

At least two individuals in the video seemed to be carrying weapons but most were unarmed. The Apache pilots also appeared to mistake a camera carried by one of the Reuters employees for a rocket-propelled grenade launcher or RPG.

At one point, the Apache pilots told controllers they had spotted "five to six individuals with AK-47s" and asked for permission to "engage."

The Apache pilots then opened fire with the helicopter's cannon, with one of them then saying there are a "bunch of bodies lying there."

"Look at those dead bastards," one said in the recording, to which another replied: "Nice."

Shortly after the initial shooting, a van arrived to pick up the dead and wounded and it was fired upon by the Apaches. Two children in the van were injured and later evacuated by US ground troops.

A US military official in April did not dispute the authenticity of the video but said it "doesn't give new information, it just gives footage."

"We had insurgents and reporters in an area where US forces were about to be ambushed," the official added.

"At the time we weren't able to discern whether (the Reuters employees) were carrying cameras or weapons."

According to the army, Manning was charged on Monday with 12 counts of misconduct in breach of both US military and criminal law.

WikiLeaks, on their Twitter feed @wikileaks, said: "Private Manning charged with disclosing iraq-slaughter video. Trigger happy Apache crew remain uncharged."