The official, asking not to be identified, said the administration is reviewing its policies toward Peru in international lending organizations. Bilateral aid programs, both military and non-military, also are being examined, the official said.
The official acknowledged that an across-the-board aid cut is not being considered because of the impact that would have on Peru's majority poor population.
Among the programs not likely to be affected are those that support health clinics and assist farmers in gaining access to markets for their products, the official said.
He added that it would be difficult to cut back on the U.S. counter-drug program in Peru because that issue is a high administration priority.
Peruvian President Alberto Fujimori has been a key ally in the drug war. The latest State Department report on the drug situation worldwide, issued in March, says Peru "has made enormous strides toward its goal of eliminating illegal coca cultivation."
U.S. counter-drug assistance for fiscal year 2000 is estimated at $48 million. The administration hopes to maintain that level in the next fiscal year.
Figures on other aspects of the U.S. assistance program in Peru were not immediately available.
Despite Peru's cooperation in the drug war, the administration believes it is important to send a strong message of disapproval over Peru's authoritarian turn, the official said.
He added that a complacent U.S. attitude could tempt anti-democratic forces elsewhere in the region to move against constitutional governments.
The Organization of American States permanent council is expected to approve a resolution on Wednesday condemning Peru's action, according to the official.
President Fujimori was re-elected Sunday in a runoff that his main challenger boycotted. The U.S. State Department called the election "invalid," and violent protests in the South American nation ensued, reports CBS News Correspondent John Roberts reports.
Police in Lima clashed with student protesters and government opponents called for the election results to be thrown out.
Fujimori faced fraud allegations after winning a slim majority in the first round of the election. He refused requests to postpone Sunday's runoff and would not allow independent monitors. In response, opposition candidate Alejandro Toledo dropped out and urged supporters to cast protest ballots.
Fujimori kept a low profile Monday, avoiding a public celebration of an election victory.
President Clinton warned last week that he would review relations with Peru if Sunday's vote was not postponed to allow time to clear up concerns over glitches in electoral computers, media bias and state handouts to the poor.
Fujimoi, 61, also faces possible reprisals from the rest of the international community as he heads to begin a third consecutive five-year term after an election snubbed by opposition and international monitors alike.
Toledo was greeted Sunday night by a crowd tens of thousands strong which hailed him as the real victor.
The opposition press celebrated what it said was a poor result for Fujimori given that his only rival refused to participate and that the absence of independent monitors had left the field open to possible pro-government fraud in a country with one of the region's worst rights records.
"Fujimori ran the race on his own and still lost!" was the full-page headline of daily La Republica.
Toledo said the election was void and Fujimori had become a dictator. He promises a campaign of non-violent resistance modeled on the ideals of U.S. civil rights campaigner Martin Luther King and Indian independence hero Mahatma Gandhi.
With about 70 percent counted, Fujimori had 50.3 percent of votes cast, while Toledo had 16.5 percent. But another 32.2 percent cast invalid votes -- apparently heeding Toledo's call to deface the ballots.
Just a few blocks away, tens of thousands of Toledo supporters cheered him as if he was the victor. The 54-year old son of a poor Andean peasant who rose to become a World Bank economist shouted himself hoarse as he vowed a campaign of peaceful resistance to overthrow Fujimori and force fresh elections.
Pro-Fujimori television ignored Toledo's rally the only one held on election night and one of the country's most watched stations preferred to show Pokemon cartoons.
Toledo had called on his supporters to stay away from the polls or else to deface their voting papers with the words "No to Fraud." Voting is compulsory in Peru and those who do not cast ballots risk a fine equivalent to $33.