Baghdad, Aug 25: An Iraqi security guard at the UN headquarters in Baghdad helped attackers launch the suicide bombing there which killed 23 people, including the world body's top envoy to the country, US-run Iraqi television reported yesterday. "Iraqi official sources confirmed a security agent had given information to the plotters of the attack in which a car laden with explosives (was detonated) next to the office of Sergio Vieira De Mello," the UN special envoy, the Iraq media network television channel said.

The television did not say if the security guard had been arrested.

"He had given them the building layout, including the office of Vieira De Mello," it said. The FBI has begun questioning un security guards, a UN source said.

A UN official told a news agency on Friday that Iraqi security guards at the UN's Baghdad headquarters aided the plotters of the attack.

"They clearly had support from Iraqi security guards inside who gave intelligence to the planners of the attack," the official said, speaking on condition of anonymity.

"It was a well prepared attack. The target was Sergio Vieira De Mello, that much is clear," he said.

"They knew where Vieira De Mello's office was and they knew they would find him in his office and they packed the vehicle with the maximum amount of explosives. The vehicle was positioned in the spot where it would make that part of the building collapse," the official said. Bureau Report