The commander of a US army base where a soldier shot three colleagues says an "escalating argument" was the most likely cause of the attack.

Barack Obama has been rallying American troops in Texas, exactly two years after he promised to end the Iraq war.

President Barack Obama will mark a promise kept in a speech today, declaring the end of America’s combat mission in Iraq and wagering the wobbly Baghdad government can hold together against a still-dangerous uprising.

An American soldier who had told his family he did not want to return to Iraq apparently killed himself in a Puerto Rican motel days before he was to join his unit and head back to the war zone, police in the US territory said today.