WikiLeaks has posted a video on its website which it claims shows the killing of civilians by the US military in Baghdad in 2007.

The website's organisers say they were given the footage, which they say comes from cameras on US Apache helicopters and that they decrypted it. They would not reveal who gave it to them.

The WikiLeaks site campaigns for freedom of information and posts leaked documents online.

The Pentagon has confirmed to Al Jazeera the authenticity of the footage, but no official Pentagon statement was made.

The video shows a US military helicopter firing repeatedly on a group of men - some of whom were unarmed civilians.

Eleven people were killed in that attack, including a photojournalist with the Reuters news agency and his driver. Two children were injured.

So, what are the rules of engagement and is this kind of violence justified?

To discuss this, Inside Story is joined by: Glen Greenwald, a liberal writer, Bill Roggio, a former soldier who fought in Iraq, Steven Livingston, a professor of international relations and media at George Washington University.

This episode of Inside Story aired on Wednesday, April 7, 2010.