The Justice Department announced a murder indictment Tuesday against a Colombian rebel group and six of its members in connection with the deaths of three Americans.

Attorney General John Ashcroft said members of the Revolutionary Armed Forces of Colombia, or FARC, kidnapped the Americans in February 1999 as they worked with Indians in northeastern Colombia. Days later, the kidnappers shot them, Ashcroft said.

Those slain were Terence Freitas, Ingrid Washinawatok and Lahee'Enae Gay. Ashcroft said the three "went to Colombia to do good and instead were met with great evil." The bodies were found in nearby Venezuela.

"Today's action is a step toward ridding our hemisphere of the narcoterrorism that threatens our lives, our freedom and our human dignity," Ashcroft said.

Ashcroft and the Justice Department have increasingly pursued the world's largest drug traffickers as another way to stem the flow of cash and weapons to terrorists.

A senior Justice official, speaking on condition of anonymity, said those indicted Tuesday were not in U.S. custody. Ashcroft said U.S. officials will work with authorities in Colombia to extradite them if they are captured.

Luis Alberto Moreno, the Colombian ambassador to the United States, said: "The Colombian government will study the request of extradition by the U.S., and if approved by government and tribunals, those individuals will be extradited when they are arrested. I do not have any information if one or more of those mentioned in indictment are arrested."

Colombia's attorney general Luis Camilo Osorio welcomed the indictment as a weapon against terrorism. "Anyone in the international community that can help us combat terrorism is welcome," he said.

The indictment, returned by a grand jury in U.S. District Court in Washington, accused the FARC organization and the individuals of murder, conspiracy to commit murder, using a firearm during a crime of violence and aiding and abetting.

Washington broke off tentative peace contacts with FARC following the deaths of the three Americans.

The grand jury said FARC and its members considered U.S. citizens to be military advisers and thus legitimate military targets.

The six individuals were identified as German Briceno "Granobles" Suarez; El Marrano, also known as Fernando or "The Pig"; Jeronimo; Gustavo Bocota Aguablanca; Nelson Vargas Rueda; and Dumar. Only single names were provided for Jeronimo and Dumar, although the indictment included grainy photographs of the two along with a picture of El Marrano.

Briceno was convicted in absentia in Colombia last September of homicide, kidnapping and rebellion and sentenced to 40 years in prison for the 1999 murders of the three Americans. A brother of the senior military leader of FARC, Briceno has not been captured.

The indictment said Briceno instructed FARC members to seize the Americans and later told a colleague over the radio, "Those that don't pay get their heads chopped off." Days later, a FARC member radioed that one of the hostages appeared to be ill and dying, and Briceno replied that he was unconcerned, the indictment said. The shootings took place five days later.

"Just as we fight terrorism in the mountains of south Asia, we will fight terrorism in our own hemisphere," Ashcroft said.

Ashcroft has said previously that members of FARC have killed 13 Americans since 1980 and kidnapped more than a hundred others, including three U.S. missionaries in 1993 who are believed to have been killed.

FARC has been frequently implicated in cocaine running that affects the United States, U.S. officials have said.

The rebel group is estimated to have 17,000 members and is one of three main rebel groups involved in Colombia's long strife.

Last month, Ashcroft announced the indictment on cocaine charges of three FARC members who conspired to deliver planeloads of cocaine into the United States from 1994 to February 2001.

The three included Tomas Molina Caracas, whom the government said commands FARC's 16th Front, which operates in eastern Colombia and controlled an airstrip near Barranco Minas. The government regards the airstrip as essential for carrying processed cocaine out of the rural region. Molina is known in the region as "El Negro Acacio."

The others identified as FARC members in that indictment were Carlos Bolas and a man known to the government only as "Oscar El Negro."