Officials say the Bush administration will announce on Tuesday the lifting of the long-standing ban on the use of U.S. passports for travel to Libya. The move is the first tangible step to reward Libya for its decision in December to dismantle its nuclear program and halt other weapons-of-mass-destruction activity.

Officials here say the passport ban is being lifted, and the administration will remove some related financial restrictions, in order to permit legal travel to Libya by Americans for the first time in more than two decades.

The move had been widely expected since late last year when it was announced that Libya, capping months of secret negotiations with the United States and Britain, was ending a covert nuclear weapons program and allowing experts from the two countries and the International Atomic Energy Agency to observe the dismantling.

Earlier this month, the United States posted a full-time diplomat in the U.S. interests section at the Belgian embassy in Tripoli in the first official presence since the American embassy was closed and its staff pulled out amid high tensions in 1980.

The officials say the Bush administration will also invite Libya to open a diplomatic interests section in Washington, though they said a resumption of full relations must await other steps by Libya to among other things satisfy U.S. officials that it no longer has links to terrorists.