The question as to who was behind the deadly truck bombing at a hotel housing U.N. employees in Baghdad on Tuesday became the center of debate following the huge explosion that left many trapped under tons of rubble.
A cement truck reportedly tore through a security gate surrounding the Canal Hotel (search) — the headquarters for the U.N. mission in Iraq — drove into the lobby and exploded, destroying about one-third of the building and damaging surrounding structures.
President Bush vowed that the bombings, which left at least 15 dead, would not thwart the U.S. war on terror.
"By their tactics and their targets, these murderers reveal themselves once more as enemies of the civilized world," Bush said in an address from his ranch in Crawford, Texas. "The civilized world will not be intimidated, and these killers will not determine the future of Iraq."
Secretary of State Colin Powell said "We will not be deterred by such immoral acts."
"The terrorist bombing that occurred at U.N. headquarters in Baghdad today is a heinous crime against the international community and against the Iraqi people," Powell said. "The international community must renew its commitment to working with the majority of the Iraqi people who seek to build a free and stable country."
Added Attorney General John Ashcroft: "This morning's attacks confirms the worldwide terrorist threat is real, it is eminent … they seek to kill us abroad and at home but we will not be deterred from our responsibility to preserve American life and liberty."
Based on the nature of the bombing, many experts agree that the bombers likely were die-hard loyalists of former Iraqi President Saddam Hussein and could possibly be linked to Usama bin Laden's Al Qaeda (search) network. As of yet, no one group claimed responsibility for the attack.
"I think what this shows is an increase in the level of organization of the opposition we face," Rep. Jerrold Nadler, D-N.Y., told Fox News. "We have to assume a further escalation of violence against coalition forces and allies."
"There seems to me rather stark evidence in the heart of Baghdad that terrorists are afoot, even Al Qaeda afoot, in the provinces of Iraq," said Rep. Mike Pence, R-Ind.
Added Rep. Chris Cox, R-Calif., chairman of House Select Committee on Homeland Security: "This is a classic confrontation of the forces of civilization against those who would destroy civilization."
Other experts agreed that the attack was designed to send the message that opposition to Western world influence and its presence in the region is alive and well in the region.
Fox News military analyst Maj. Bob Bevelacqua said the bombing is terror groups sending the message: "If you're going to assist the United States, we're going to come after you."
Denis Halliday (search), former assistant secretary-general of the U.N., told Fox News: "this is a tragedy of large proportion but I guess it shows some of the anger directed against the occupation but also against the United nations, which would be seen as the collaborator in this situation."
Paul Bremer, the U.S. administrator in Iraq, told Fox News that the bombing was a "vicious attack" against people working at the United Nations, many of which were Iraqis, who "had no political motive."
"The attack has to be seen as an attack on the Iraqi people — an effort to stop the reconstruction here," Bremer said.
Bremer also expressed his condolences to the friends and family of Sergio Vieira de Mello, one of the highest-ranking officials at the United Nations who died hours after the blast after being trapped under the rubble.
"He was a very good friend," Bremer said. "I have lost far too many friends to terrorism in the past years and this is just the latest one. It's a perfect outrage."
Ambassador Dennis Ross, Fox News foreign affairs analyst, said the message was directed at the Iraqi people.
"What they're [terrorists] trying to convey right now is that nothing is going to go back to normal — that those who are determined to prevent the United States from succeeding will continue, will persevere … every time something is done to build infrastructure, it will be destroyed."
At the United Nations, global officials sought to maintain a unified front, saying the latest attack will not deter humanitarian and reconstruction efforts in Iraq.
"All of us at the United Nations are shocked and dismayed by today's attack, in which dozens of our colleagues have been injured" and an unknown number killed, Secretary-General Kofi Annan said in a statement Tuesday.
Annan, who is on vacation in northern Europe, said he hoped those responsible for the attack would quickly be brought to justice.
Acting U.N. Security Council President Fayssal Kendad said such attacks "cannot break the will of the international community in its efforts to help the people of Iraq.
"These attacks are unacceptable and they [terrorists] must be brought to justice."
"Our response has to be to show the strength of the United Nations in these circumstances," added Adolfo Aguilar Zinser, Mexico's ambassador to the U.N. "An act of terrorism … simply indicates that terrorists respect no boundaries."
Bertrand Ramcharan, acting U.N. high commissioner for Human Rights, called the attack "a despicable act directed at people whose only aim is to assist the people of Iraq recover from war and years of oppression."
And no one thinks these terrorist attacks will stop anytime soon.
"I do believe we're going to see more and more attempts" to thwart reconstruction efforts, former U.N. weapons inspector Tim Trevan told Fox News. "It's very difficult to stop, as any nation who's had terrorism knows."
He said it's vitally important that the Iraqi population sees improvements in their living conditions in order to "destroy the base of support for terrorists."
Sen. Edward Kennedy, D-Mass., who serves on the Senate Armed Services Committee, immediately condemned the bombing.
"It cannot deter our nation from working with the international community to secure the peace, rebuild Iraq, minimize the burden on our troops, and deliver on the promise of democracy for the Iraqi people," Kennedy said.
U.S. House and Senate members who were visiting military sites in Iraq Tuesday when the bomb ripped through the Canal Hotel will hold a press conference in Kuwait around 3 p.m. ET.
The blast occurred about 4:30 p.m. local time, hours after the U.S.-led coalition in Iraq announced that Taha Yassin Ramadan, a former Iraqi vice president known as "Saddam's knuckles" for his ruthlessness, was turned over to U.S. forces in the northern city of Mosul.