BOGOTA - (AP) -- The chief of Colombia's brutal paramilitary groups, Carlos Castaño, said that if the United States seeks his extradition for drug trafficking, he will surrender to prove his innocence, according to an interview published Sunday.

  The right-wing militias agreed to re-create their national umbrella organization, with Castaño leading it again, during a clandestine meeting in the mountains of northern Colombia, according to a letter posted on the group's website.

  The organization, known as the United Self-Defense Forces of Colombia, or AUC, splintered in July after Castaño said some of the militias were engaged in drug
  trafficking and kidnapping, instead of focusing on their primary task of fighting leftist rebels.

  The AUC, considered a terrorist organization by Washington, is made up of militias that are accused of the majority of the massacres in Colombia's bloody civil war. About 3,500 people die every year in the conflict that has lasted 38 years.

  The AUC said in the letter on its website that the organization was reforming because the Colombian government couldn't protect many regions of the country from the rebels.

  ''We hold the guerrillas exclusively responsible for Colombia's war and for its consequence, that Colombians have been forced to take up arms as the only way to live,'' said the letter, signed by Castaño, Salvatore Mancuso, the group's military chief, Castaño's brother, Vicente, and 15 local militia leaders.

  The letter was addressed to U.N. Secretary General Kofi Annan, U.S. ambassador to Colombia Anne Patterson, Colombia's peace commissioner and the president of the Colombian Episcopal Conference.

  U.S. officials have declined to comment on reports that they were considering asking for Castaño's extradition on charges of drug trafficking.

  ''If the [rumor] about extradition is true, tomorrow I will turn myself in to the United States,'' Castaño told Colombia's largest newspaper, El Tiempo. ``That is the best way to defend myself. I prefer to clarify there, rather than respond here, for things I haven't done.''

  Sen. Rafael Pardo, a former defense minister and negotiator in peace talks with the now-defunct M19 rebel group, called Castano's offer to turn himself in a "publicity stunt.''

  ''Why doesn't he turn himself in to Colombian authorities who do have warrants for him?'' Pardo said.

  Meanwhile, rebels released nine people Sunday taken hostage three weeks ago, government officials said. Eighteen others kidnapped the same day were still being
  held.