"We are firmly committed to doing whatever we can to secure these treasures to the people of Iraq," FBI Director Robert Mueller told a news conference at the Justice Department.
He said the agents would "assist with criminal investigations" and with the recovery of stolen items.
Mueller also said the FBI was cooperating with the international law enforcement organization Interpol in issuing alerts to all member nations to try to track any sales of the artifacts "on both the open and black markets."
Meanwhile, experts at an international meeting said some of the looters who ravaged Iraqi antiquities appeared highly organized and even had keys to museum vaults and were able to take pieces from safes.
The U.N. cultural agency gathered some 30 art experts and cultural historians in Paris on Thursday to assess the damage to Iraqi museums and libraries looted in the aftermath of the U.S.-led invasion.
Although much of the looting was haphazard, experts said some of the thieves clearly knew what they were looking for and where to find it, suggesting they were prepared professionals.
"It looks as if part of the looting was a deliberate planned action," said McGuire Gibson, a University of Chicago professor and president of the American Association for Research in Baghdad. "They were able to take keys for vaults and were able to take out important Mesopotamian materials put in safes."
Cultural experts, curators and law enforcement officials are scrambling to both track down the missing antiquities and prevent further looting of the valuables.
The pillaging has ravaged the irreplaceable Babylonian, Sumerian and Assyrian collections that chronicled ancient civilization in Mesopotamia, and the losses have triggered an impassioned outcry in cultural and artist circles, including the recent resignation of President Bush's cultural advisor.
Distressed by what he called a U.S. failure to protect Iraq's cultural heritage, The Washington Post reported head of President Bush's Advisory Committee on Cultural Property Mark E. Sullivan submitted a letter of resignation on Monday which stated, "The tragedy was not prevented, due to our nation's inaction."
Many fear the stolen artifacts have been absorbed into highly organized trafficking rings that ferry the goods through a series of middlemen to collectors in Europe, the United States and Japan.
Officials at the UNESCO meeting at its headquarters in Paris said the information was still too sketchy to determine exactly what was missing and how many items were unaccounted for.
The experts, who included Iraqi art officials, said some of the most valuable pieces had been placed in the vault of the national bank after the 1991 Gulf War, but they had no information on whether the items were still there.
They were united in calling for quick action to track down the pilfered items.
"I have a suspicion it was organized outside the country, in fact I'm pretty sure it was," said Gibson. He added that if a good police team was put together, "I think it could be cracked in no time."
Koichiro Matsuura, director-general of the U.N. Educational, Scientific and Cultural Organization, began the meeting Thursday by calling for a U.N. resolution imposing a temporary embargo on trade in Iraqi antiquities.
Matsuura said it was urgent to repair the antiquities that remain and to keep them from the hands of those who traffic in the lucrative market of stolen objects.
"It is always difficult, when communities are facing the consequences of an armed conflict ... to plead the case for the preservation of the cultural heritage," Matsuura said.
Matsuura said he would ask U.N. Secretary-General Kofi Annan to seek a resolution against illicit trafficking that would also impose an embargo "for a limited period" on the acquisition of Iraqi cultural objects. Such a resolution would also call for the return of such items to Iraq, he said.
In addition, Matsuura said the establishment of a nationwide "heritage police" was necessary to watch over cultural sites and institutions. Such a force could be set up by "the authorities on the ground," an apparent reference to U.S. and British forces in Baghdad.
The UNESCO chief equated preserving cultural heritage with preserving cultural identity and "preserving the basis of social cohesion."
"To preserve the Iraqi cultural heritage is, in a word, to enable Iraq to successfully make its transition to a new, free and prosperous society," he said.
He reiterated a call for governments to adopt emergency legal and administrative measures to prevent anyone's importing objects from Iraq and to museums and art dealers to refuse transactions in such objects.
A database of all cultural objects needs to be quickly established so police, museums, customs authorities can act against any traffickers, he said.