A top Bush administration official is calling on Libya to repudiate terrorism as the next step toward normalizing U.S.-Libyan relations.

Assistant Secretary of State William Burns issued the appeal as Washington lifted a travel ban against Tripoli as a reward for progress made by Libya toward dismantling its weapons of mass destruction programs.

At a Senate Foreign Relations Committee hearing, Assistant Secretary Burns said U.S.-Libyan relations are at "a turning point," following decades of hostility.

He said Libya has taken "significant steps" toward eliminating weapons of mass destruction and the missile systems to deliver them, since Libyan leader Moammar Gadhafi pledged to dismantle such weapons two months ago.

The United States rewarded Libya Thursday by lifting the two-decades-old restrictions on Americans traveling to that country and allowing U.S. oil firms to go to Tripoli to negotiate deals ahead of U.S. plans to lift trade sanctions imposed in the 1980's.

While praising Libya for the progress it has made in dismantling its weapons programs, Secretary Burns called on Tripoli to do more to end its ties to terrorism.

"Libya remains on the [State Department's] list of state sponsors of terrorism," he said. "Before this changes, we will need to confirm that Libya has implemented a strategic decision to repudiate terrorism as a tool of foreign policy and to break any residual ties it may have with any terrorist organization."

Mr. Burns said U.S. relations with Libya will be guided by Libyan actions, not promises, and said any backtracking of Libya's commitments would result in a re-evaluation of the bilateral engagement.

The warning was prompted by comments from Libya's Prime Minister earlier in the week that the country had no role in the 1988 bombing of Pan Am Flight 103, which killed 270 people, including 181 Americans.

Libya's news agency immediately disavowed the comments, but not before they caused concern in Washington. Secretary Burns. "We have been crystal clear that U.S.-Libyan relations can only be rebuilt if we develop confidence in the Libyan regime's commitment to repudiate its past record of support for terrorism and search for weapons of mass destruction," he said. "We will not compromise this principle."

One Libyan intelligence agent was convicted and another acquitted by a Scottish court for the bombing of Pan Am Flight 103.

On a more positive note, the administration hopes Libya's pledge to abandon weapons programs will be an example for other countries, including North Korea and Syria, to follow.

Secretary of State Colin Powell made the point at another Senate hearing earlier in the day. "We hope that this will be a signal to other countries around the world that it is fool's gold, it is ridiculous to invest in these kinds of technologies, because you will not scare the United States of America, you will not scare our coalition partners, all you are doing is denying yourselves the opportunity for a better relationship with the United States and with the rest of the civilized world," he said.

Foreign Relations Committee Chairman Richard Lugar suggested that Libya's example might persuade other nations in the region to seek better relations with the United States. He noted such an opportunity could come this week, when Libya hosts a summit of African leaders.

"Having cheerful Libyans telling them that Americans might be good people, that they might be worth dealing with, may not settle well right off the bat," he said. "We are talking about the Libyans changing their mindset. They are about to deal with a whole group of people who have mindsets. In one conference day or two they may not change their minds, still this is sort of an important juncture."

The two-day summit opens in the Libyan coastal city of Sirte Friday.