Colombia's ambassador to the United States has resigned over the nomination of a disgraced former president as ambassador to France.

Andres Pastrana, himself a former president, stepped down Tuesday, saying he had little choice after President Alvaro Uribe appointed Ernesto Samper to the post.

The government later announced that Mr. Samper had turned down the post.

Mr. Samper's four-year presidency, which began in 1994, was overshadowed by allegations that his campaign accepted five-million dollars in contributions from the notorious Cali cocaine cartel. He was later cleared by the Colombian legislature.

Colombia has received billions of dollars from the U.S. to help fight illegal drug trafficking.

Mr. Uribe has picked current Foreign Minister Carolina Barco to replace Mr. Pastrana as Bogata's envoy to Washington.