Pentagon: Possible al Qaeda link in Baghdad blast
BAGHDAD, Iraq (CNN) -- Pentagon officials said Wednesday that a terror group linked to al Qaeda is emerging as a top suspect in the deadly blast at U.N. headquarters in Baghdad.
An official told CNN that intelligence reports in the past two weeks indicated Ansar al-Islam might be planning a major attack in Iraq, and a top U.S. official in the country also said he suspects the group could have launched Tuesday's strike that killed at least 17 people.
"It's part of a global war against terrorism that was officially declared on us on September 11," U.S. civilian administrator L. Paul Bremer said. "It's quite clear we do have terrorists inside Iraq now."
Sergio Vieira de Mello, the top U.N. envoy in Iraq, was among those killed Tuesday, and others are believed to be dead under the rubble. (Profile of Vieira de Mello)
No one has claimed responsibility for the attack. (Bombing scene)
But Bremer said that foreign terrorists or Ansar al-Islam could have been involved in the U.N. attack and the deadly Jordanian Embassy blast on August 7.
"After the war, it appears that a number of terrorists from the Ansar al-Islam group have reinfiltrated into Iraq," Bremer said. "We are concerned about that. We also have other foreign terrorists who've been arriving from other borders."
He said people are entering the country with travel documents from countries such as Sudan, Syria and Yemen. "This we know because we have killed or captured a number of them," he said.
Pentagon officials said the bomb attack at the U.N. complex appears more sophisticated than would be expected from Saddam Hussein loyalists. However, they cautioned that members of the Mukhabarat, the former Iraqi intelligence service, would have the expertise to use explosives.
U.N. Secretary-General Kofi Annan on Wednesday vowed the world body will press ahead with its efforts in Iraq.
"We will carry on our work," he said. "We shall not be deterred. We are going to keep at it until we succeed."
Of those who carried out the attack, he said, "This is not going to serve their cause."
U.N. reassessing security
In the carnage, four people remain unaccounted for, U.N. officials said. Eighty-six people were hospitalized, and 20 are to be evacuated to Jordan for treatment, they said.
"For people who went into Iraq with only the objective of assisting the people of Iraq to be killed in such a violent and senseless manner is something that none of us will ever comprehend," Annan said.
The bombing was the single most deadly attack in Iraq since the Bush administration declared an end to major combat operations on May 1. (Full story)
Investigators said the explosives-laden truck was packed with "military-grade munitions" similar to those used by Saddam's armed forces.
Pentagon officials said a key objective is to analyze the detonator used in the attack. They said they want to determine whether a so-called "shaped charge" was used that would have forced the bomb blast in the direction of the building to achieve maximum damage.
"This was not a homemade bomb," said Tom Fuentes, the FBI agent leading the investigation. He noted that parts manufactured in the Soviet era were found among the explosives -- fragments from mortars, artillery shells, grenades and a 500-pound bomb.
Fuentes said investigators were able to comb through the area where the truck bomb detonated. They got into the bomb crater, took chemical samples, retrieved vehicle parts and found some human remains, he said.
Tuesday's attack has spurred concern over how to implement security measures in Iraq. Bremer said all foreign missions will meet Friday to talk about tougher precautions.
Asked about a report that the United Nations in Baghdad declined an offer of increased security from U.S.-led coalition forces, Annan said that even if it were the case U.N. personnel should not have been allowed to do so.
"First of all, I was surprised that we would turn down such an offer. And secondly, that kind of decision should not be left to the protected," he said. "It is those with the responsibility for security and law and order who have the intelligence which determines what action is taken."
Annan said the United Nations is reassessing its security arrangements in Iraq.
"Some mistakes may have been made; some wrong assumptions may have been made," he said, "but that does not excuse nor justify the kind of senseless violence that we are seeing in Iraq today."
U.N. spokesman Fred Eckhard said the world body had been building a 12-foot concrete wall around the converted Canal Hotel that served as U.N. headquarters. But U.N. officials wanted "to maintain a certain openness to the Iraqi people," he said.
"Security around our location was not as secure as you might find at the U.S. compound, and that was a decision we made so that our offices could be more accessible to people. We did not think at the time we were taking an unnecessary risk," Eckhard said.
Bremer said the United Nations is responsible for security at its site, as are all foreign missions.
U.S. civilian, soldier killed
In new violence Wednesday, an American working as a contracted interpreter was killed and two U.S. soldiers wounded in small-arms fire and a rocket-propelled grenade attack in the north-central city of Tikrit, U.S. Central Command said.
The names of the casualties were not released.
The city, Saddam's ancestral homeland, has been the site of much activity by coalition troops searching for wanted Iraqis.
In another incident, a U.S. soldier was killed and another injured when the heavy-duty truck they were riding in crashed into another vehicle in a supply convoy that was hit with small-arms fire, Central Command said.
Security, medical and recovery assets were dispatched to the scene.
CNN Correspondents Rym Brahimi and Barbara Starr contributed to this report.