Energy Secretary Spencer Abraham announced yesterday that almost two tons of low-enriched uranium and about 1,000 radioactive samples used for research had been removed from Iraq's Tuwaitha Nuclear Center and brought to the United States for security reasons.

The airlift of the radioactive materials was completed June 23, Abraham said in a statement, "to keep potentially dangerous nuclear materials out of the hands of terrorists." Less sensitive radiological materials -- used for medical, agricultural or industrial purposes -- were left in Iraq, according to a Department of Energy statement.

The International Atomic Energy Agency, which in the prewar period had kept the Tuwaitha uranium under seal, was told in advance of the U.S. removal, as were Iraqi officials.

Tuwaitha was once the center of Saddam Hussein's nuclear weapons effort, but its equipment was dismantled at the direction of U.N. inspectors in the early 1990s as part of the agreement following Iraq's surrender in the 1991 Persian Gulf War. The U.N. inspectors removed highly enriched uranium that could be used for weapons and shipped it for storage in Russia. The low-enriched uranium was placed under seal in storage at Tuwaitha but under the control of the IAEA.

Before the U.S.-led coalition's invasion of Iraq, as the Bush administration alleged that Hussein had reconstituted his nuclear program, Tuwaitha was a target for U.S. intelligence.

In April 2003, just days after the statue of Hussein in Baghdad was pulled down, a U.S. Marine engineering company took a close look at Tuwaitha, which is 30 miles south of Baghdad. There they found guards had abandoned their posts and looters were roaming the giant facility. At one storage building, which later was found to hold radioactive samples used in research, the radiation levels were too high to enter safely, although the entrance door stood wide open.

A month later, the Pentagon rejected suggestions that U.N. inspectors be allowed to reenter Iraq but agreed the IAEA experts could return to secure the uranium that had been under its seal for years.