Updated

The U.S. is trying to revive a program to prevent Libyan chemical, biological and nuclear scientists from working for terror groups or hostile nations, a State Department official said Thursday.

Hundreds of experts worked in Muammar Qaddafi's weapons of mass destruction programs.

After Qaddafi agreed to dismantle the programs in 2003, the U.S. launched an effort to steer Libya's WMD scientists into civilian research projects, including water desalination, oil and gas production and nuclear medicine. The effort was suspended during Libya's civil war.

The official told The Associated Press that the U.S. has asked Libya's interim government to allow Washington to re-establish contact with the scientists. The official spoke on condition of anonymity because of the sensitivity of the issue.

Libya's new leaders have expressed an interest in working with the U.S. on the scientist program and other counterproliferation efforts, the official said, but so far they have not responded formally.

Bilal Saab, a Middle East expert at the Monterey Institute of International Studies in California, said securing Libya's weapons of mass destruction and the expertise needed to produce them is a priority for the U.S. At the same time, Saab said Libya's interim leaders have different concerns, including their struggle to defeat the remaining Qaddafi loyalists and unify the country.

The U.S. has sought to keep track of Libya's unconventional weapons experts during the civil war, the State Department official said, and has found no direct evidence that any were recruited to work in illicit weapons programs.

In the past few days, a few Libyan WMD scientists, including bioweapons experts, have re-established contact with U.S. officials. Meanwhile, the official said, Washington has worked with U.S. scientists at nongovernment groups and national laboratories to draft a list of key Libyan researchers who need to be located.

Word of the U.S. effort to re-establish contact with Qaddafi's scientists came as Britain and France promised to release billions of dollars in frozen assets to the interim government and to push NATO strikes against Qaddafi's last strongholds.

Qaddafi agreed to dismantle his WMD research and production programs in the aftermath of the U.S. invasion of Iraq and under intense economic pressure from international sanctions.

After 2003, Libya surrendered its nuclear weapons-related equipment and materials, in addition to 1,300 tons of chemicals that could have been used to make nerve agent, which can kill in tiny doses. Under U.S. and Western supervision, Libya also destroyed almost 3,600 chemical bombs and about half of its stockpile of 23 tons of mustard agent.

Qaddafi never completed the process of WMD disarmament, leaving Libya with about 2,000 tons of uranium yellowcake, partly refined uranium ore, as well as 11 metric tons of mustard agent, radiological materials that might be used in a so-called dirty bomb and 200 Scud-B ballistic missiles.

In February 2004, President George W. Bush announced that the U.S. was launching an effort to create civilian jobs for Libya's weapons experts. But current and former officials describe Libya's cooperation in the program as limited.

The State Department official said that while Qaddafi provided relatively free access to his nuclear scientists and research biologists, he restricted contacts with his chemical weapons experts to the point of assigning minders to monitor and censor interviews.

Libya had extensive experience manufacturing chemical arms and used them against its southern neighbor Chad in 1987.

Qaddafi's nuclear program by contrast had made limited progress and his biological weapons effort was largely confined to laboratory research.

In recent years, Libya further restricted its cooperation with the U.S. in counterproliferation programs.

According to an internal State Department cable released by WikiLeaks, Libya in 2009 temporarily blocked the shipment out of the country of its last stocks of weapons-grade uranium.

The cable quoted Qaddafi's son Saif saying the regime was unhappy with the slow pace and narrow scope of U.S. financial and military aid.

The U.S. has run similar programs for weapons experts in Russia, Iraq and 42 other countries worldwide. Some Iraqi and Russian scientists with crucial skills have been brought to the U.S., the official said, but the program aims to find civilian work for most scientists in their homelands.

The U.S. is worried about the fate of some of Libya's conventional weapons. Qaddafi amassed as many as 25,000 portable anti-aircraft missiles, called MANPADS, before the civil war, raising concerns that the looted weapons could be used to target civilian aircraft.

News reports suggest that some unguarded caches of the mostly Russian-built mobile weapons already have been looted.

The State Department recently sent a U.S. weapons disposal expert and several private contractors to Tripoli to help in the hunt for MANPADS and other loose munitions.

The U.S. also is spending $3 million for two international weapons disposal teams to search and disable similar arms elsewhere in Libya.