International experts have shipped 20 kilograms of weapons-grade uranium from Libya to Russia in previously unannounced operations since Moammar Gadhafi decided in 2003 to end his quest for weapons of mass destruction, a U.S. agency said Thursday.

National Nuclear Security Administration spokeswoman Julie Smith said Thursday the latest shipment of three kilograms of highly enriched uranium had been extracted over a two-day period this week from Gadhafi's Tajura research reactor. The facility is near the Mediterranean coast about 10 miles east of Tripoli, Libya's capital.

"We had to wait to announce it to make sure it had arrived safely," Smith said. The other shipment of 17 kilograms was returned to Russia in 2004.

CountryWatch: Libya

The agency's announcement said the operation "is part of a multistep project to remove all Russian-origin HEU material from Libya."

The agency said in a news release that the fresh highly enriched uranium, which could have been used in nuclear weapons, would be blended down to safer low enriched uranium and returned.

Libyan leader Gadhafi renounced weapons of mass destruction and all links to terrorism in late 2003. A year later, in September 2004, the United States began easing sanctions against Libya, renewing commercial air links and restoring Libyan access to $1.3 billion that had been frozen.

In making that announcement, Scott McClellan, then the White House spokesman, said Libya had facilitated removal of "all significant elements of its declared nuclear weapons program," destroyed its chemical munitions and removed highly enriched uranium and equipment for uranium enrichment.

Russia announced a week earlier that Russia had undertaken to recover highly enriched uranium it had shipped to civilian research reactors to reduce chances that the material might be obtained by terrorists. Among countries mentioned was Libya.

Thursday's announcement said approximately 189 kilograms of highly enriched uranium had been returned to Russia in 13 shipments from Serbia, Romania, Bulgaria, Uzbekistan, Latvia, the Czech Republic and Libya.

It said experts from the International Atomic Energy Agency, Libya, Russia and the United States handled the recovery operation under the nuclear security administration's Global Threat Reduction Initiative.

"At the Tajura Research Center, the HEU was loaded into three specialized transportation containers provided by the Russian Federation," the administration said.

"NNSA technical experts and IAEA safeguards inspectors monitored the process to load the fuel into canisters," which were airlifted under guard from an airport near Tripoli to a secure facility in Russia.