Bush administration officials alleged yesterday that Syria has developed a hit list targeting senior Lebanese political figures in an attempt to regain control of its neighboring state, just six weeks after Syria said it had ended almost three decades of military occupation.

"These are threats against some of the most prominent Lebanese political leaders. The purpose would be to create instability and to create internal strife," a senior administration official said. After a brief lull in Syrian interference in Lebanon, senior Syrian intelligence personnel have been seen back in Lebanon, particularly over the past week, the official added.

Secretary of State Condoleezza Rice said yesterday that the United States is concerned about a potential "pattern" of political killings. "What we don't want is that there is a pattern now of assassination of key figures because that would be very, very destabilizing in Lebanon, and I think it would have to point a finger at those forces that have been destabilizing in Lebanon," Rice said on "The Charlie Rose Show."

Lebanese opposition leader Walid Jumblatt also expressed concern yesterday about the potential for assassinations after the car bombing last week of a leading journalist critical of Syria. "Probably there is a decision -- with the knowledge or without the knowledge of President [Bashar] Assad -- to continue the assassinations," he said on a Lebanese television talk show.

The Bush administration is also concerned about the return of Syrian intelligence because Lebanon is now halfway through a four-phase election for parliament, which will in turn form a new government. Syria has dominated Beirut's government since shortly after it first deployed troops there in 1976, initially under an Arab League mandate to try to quell Lebanon's civil war.

Although Syrian troops have pulled out under terms mandated in a U.N. resolution, Rice said the United States has doubts about the withdrawal of its intelligence agents. "We need to keep pressure on the Syrians to be transparent about what they're doing in Lebanon," she said. "We're being very clear to people that we want an international spotlight on what is going on in Lebanon so that the Lebanese people can carry out their elections in . . . a place that is free of this kind of foreign influence," Rice said.

The senior administration official said that a "variety of credible Lebanese sources" had said Damascus has developed a "hit list" of senior Lebanese political leaders, and that the sources had reported seeing "familiar figures" from Syrian intelligence back in Lebanon. "There are efforts by Syrians to put back in place the system of intimidation," he added.

At the United Nations, Syrian Ambassador Fayssal Mekdad said that any intelligence operatives in Lebanon were from France, the United States or Israel. "I am sure there are no Syrians there. Let them investigate themselves," Mekdad told Reuters.

The United Nations is also concerned about Syria's presence in Lebanon. U.N. Secretary General Kofi Annan said yesterday that he may send a U.N. verification team back to Lebanon. In the meantime, U.N. envoy Terje Roed-Larsen is being dispatched this week to Damascus for talks with the Assad government about its presence in Lebanon.

Syria's return to Lebanon would be a major violation of U.N. Resolution 1559, co-sponsored by the United States and France, which demanded a total Syrian withdrawal from its tiny neighbor. U.S. and U.N. officials estimated that Damascus had 14,000 troops and 5,000 intelligence officials. Damascus said the last troops pulled out on April 28.

"We are now receiving reports that there may be elements that are still there, and we are considering the possible return of the verification team to ascertain what's going on," Annan told reporters.

The U.S. and U.N. concerns follow the assassination of two leading opponents of Syria's intervention. Former Lebanese prime minister Rafiq Hariri, 19 aides and security guards were killed by a bombing of his motorcade on Feb. 14. And prominent journalist Samir Kassir, who often wrote about Syrian intervention in Iraq, was killed in a sophisticated car bombing on June 2.

Rice repeated the U.S. demand yesterday for an international investigation into the trend. "We need to be very clear that we expect a full investigation of the assassination of Mr. Kassir, following on the assassination of Mr. Hariri," she said.

U.S. officials said Syrian intelligence is using Palestinian refugee camps. "They have figured out that one of the places they might be able to hide in is those camps," which are not controlled by the Lebanese Army, the senior administration official said.

The U.S. allegations, ironically, come on the same day that Syria's ruling Baath Party called for improving diplomatic relations with the United States. The final communique of the party congress called for a "constructive dialogue" with Washington and "an exchange of visits on all levels," according to Syrian television.

Lebanese guards flank U.N. investigators who were at the site where former prime minister Rafiq Hariri died in a bombing.