A U.S. congressman has met with a Colombian rebel group that was declared a terrorist organization by the Clinton administration after its members killed three Americans in March.

Rep. William Delahunt (D-Mass.) met Thursday in a southern Colombia guerrilla stronghold with Raul Reyes, a senior commander of the Revolutionary Armed Forces of Colombia (FARC).

Delahunt said he had a frank discussion with Reyes and expressed Congress's outrage over the deaths of the Americans, who were abducted and killed by a FARC unit while working in Colombia with a local Indian tribe.

The Clinton administration announced it was severing contacts with the FARC after the killings of American indigenous rights activists Ingrid Washinawatok, 41, of New York City and the Menominee reservation in Wisconsin; Lahe'ena'e Gay, 39, of Hawaii; and Terence Freitas, 24, of Los Angeles. U.S. officials demanded the group turn over the killers as a condition for continuing a dialogue aimed at supporting peace negotiations.

The meeting took place near San Vicente del Caguan, one of five townships where the FARC has ruled openly since President Andres Pastrana evacuated all government troops in November to facilitate talks between FARC and the government.

Delahunt was accompanied by a former U.S. ambassador to El Salvador, Robert White, and aides from several other Democratic and Republican congressional offices, including that of Constance Morella (R-Md.). Also in attendance was Victor G. Ricardo, Pastrana's peace envoy.

In another development today, Colombia's main right-wing paramilitary squad freed a popular senator, Piedad Cordoba, who was abducted May 21 in Medellin. Cordoba said her captor, Carlos Castano, head of the 5,000-member United Self-Defense Forces of Colombia, should be included in any peace talks.

In neighboring Venezuela, officials said hundreds of Colombians poured across the border today, fleeing increased fighting between Marxist rebels and right-wing paramilitaries.