A big blast, caused by a car bomb, on Tuesday rocked the area around a hotel housing the U.N. headquarters in northeast Baghdad. Unconfirmed reports said at least 17 people were killed in explosion. A senior U.S. official confirmed that the U.N. Special Representative in Iraq, 55-year-old Brazilian Sergio Vieira de Mello, had died after being trapped in the rubble of his office after the blast. Earlier, it was reported that he was among many people badly wounded. "Sergio Vieira de Mello's office was destroyed and Sergio himself was hurt," U.N. spokesman Fred Eckhard said in New York. Additionally, a senior UNICEF official was seriously wounded in the blast, U.N. officials said. Spokeswoman Veronique Taveau said that Benon Sevan, director of the UN oil-for-food program in Iraq, was also wounded while giving a press conference. Bernard Kerik, the former New York City police commissioner who is rebuilding the Iraqi police force, told reporters that evidence suggested the attack was a suicide bombing. "There was an enormous amount of explosives in what we believed to be a large truck," Kerik added. Asked if al-Qaida was behind the attack, Kerik said, "It's much too early to say that. We don't have that kind of evidence yet." **PHOTO CAPTION*** Cars burn outside the United Nations headquarters at the Canal Hotel. UN special representative for Iraq Sergio Vieira de Mello was killed in the apparent truck bomb attack.(AFP/Sabah Arar)