The State Department says a U.S. official has been posted in Libya in the first diplomatic presence of its kind since the American embassy in Tripoli was closed in 1980. The action stems from Libya's decision in December to dismantle its weapons of mass destruction program.

The Bush administration is taking an initial step toward resuming political relations with Libya by assigning an American diplomat to the Belgian embassy in Tripoli, which has looked after U.S. interests there for more than two decades.

U.S. officials and weapons experts have been traveling to and from Libya on an increasing basis in recent weeks to help facilitate the dismantling of its nuclear weapons and missile programs.

State Department spokesman Richard Boucher says posting the diplomat is in keeping with President Bush's stated intention to reward Libya for its weapons decision, and will help deal with the growing contacts between the two countries.

"As the Libyan government takes these essential steps and demonstrates its seriousness, its good faith will be returned," he said. "That's what we're seeing now in terms of stationing people, and starting to work together and facilitate the work, and also keep in touch with each other."

The spokesman said he expected a Libyan diplomatic presence in Washington soon, and said other U.S. steps to restore more normal relations may be forthcoming, perhaps before the end of this month.

One action considered likely is the lifting of the long-standing ban on the use of U.S. passports for travel to Libya.

Late last year, Secretary of State Colin Powell said that restriction would be reviewed on a quarterly basis and a decision on another extension is due by February 24.

If it is lifted, it would probably be accompanied by action legalizing financial transactions for Libyan-related travel.

Senior officials of the two countries held talks in London last Friday and discussed a series of bilateral exchanges and other steps provided there is continued progress on the Libyan disarmament effort.

An obstacle to a resumption of full-scale diplomatic relations is Libya's continued presence on the U.S. list of state sponsors of terrorism.

Though that country last year took responsibility for the 1988 bombing on Pan Am flight 103 over Scotland and agreed to pay compensation, U.S. officials say they remain concerned about "residual" Libyan contacts with terrorist groups.

Mr. Boucher said U.S. officials have paid a visit to the American embassy in Tripoli, which has been padlocked since a mob attack on the premises in 1980 and the withdrawal of the ambassador.

He said officials have not yet had a chance to assess whether the damaged building, which has been under Belgian custody, would be usable as a future U.S. mission.