The United States is rejecting the reelection of Alberto Fujimori as president of Peru. Fujimori faces the toughest challenge of his political career, as the US declared his victory invalid and condemned him as a serious threat to Latin American democracy, while opposition forces in Peru mounted a campaign with the hope of toppling him.

An extraordinarily swift and harsh response from Washington implied the US may make good on its previous threats to sanction Fujimori for not postponing the balloting to give international monitors a chance to guarantee a clean count. The US position is the strongest yet against Peru, though the elections were also sternly criticized by other nations including France, Argentina and Costa Rica.

The runoff election was boycotted by Fujimori’s challenger, Alejandro Toledo. He said the outcome was rigged and urged voters to void their ballots, marking them with the words “no to fraud.”