A major US firefighters' union has launched a scathing attack on former New York mayor Rudy Giuliani amid his campaign to secure the Republican presidential nomination.
The video released by the International Association of Fire Fighters urges its members to oppose his bid for the US Presidency, questioning Mr Giuliani's leadership in the aftermath of the 11 September 2001 attacks.
Colleagues and relatives of New York firefighters who died in the attacks are filmed accusing Mr Giuliani of exploiting the tragedy in his campaign for the White House.
Titled 'Rudy Giuliani: Urban Legend', the video claims that he failed as mayor to ensure firefighters had working radios, that he based his emergency headquarters too close to the World Trade Centre site and that he called off the recovery operation too soon.
The footage contains claims that the former mayor bears responsibility for flawed radio equipment that meant some firefighters did not hear an order to evacuate the World Trade Center before it collapsed.
The politically charged video targets the heart of Mr Giuliani's campaign theme that attempts to portray him as a strong leader at a trying time.
However its claims are vehemently denied by the Giuliani campaign.
Mr Giuliani has enounced what he called a 'clearly partisan' video, and cited the IAFF's well known Democratic sympathies.
The union has endorsed many Democratic candidates in the past, including Massachusetts Senator John Kerry who ran and lost in the 2004 presidential vote.
Rudy Giuliani is considered a top contender for the Republican nomination in the 2008 race with strong results in opinion polls so far.
