Photographer: Adalberto Roque/AFP via Getty Images

Colombian authorities arrested the former guerrilla commander known as “Jesus Santrich” at the request of the U.S., potentially throwing the nation’s peace process into crisis.

Santrich and three other former guerrillas face extradition to the U.S. for a conspiracy to export 10 tons of cocaine, the Attorney General Nestor Humberto Martinez said in a televised address. Santrich, whose real name is Seuxis Hernandez-Solarte, was one of the negotiators of the Revolutionary Armed Forces of Colombia, or FARC, in its peace talks with the government in Havana.

Colombian President Juan Manuel Santos said he wouldn’t hesitate to sign Santrich’s extradition order if there were irrefutable proof of his guilt, since crimes committed after the signing of the peace accord aren’t covered by its terms. Santrich had been set to enter congress in July, taking one of the ten seats guaranteed the group under the terms of the peace deal.

FARC member Griselda Lobo, also known as “Sandra Ramirez”, who is set to take a seat in the Senate, said in a phone interview that the action was a violation of the terms of the peace accord, and that group would meet Monday to consider its reaction.

“Demobilized guerrillas who’ve been ‘bending the rules’ on narco-trafficking may see this as a signal to bail out and join the FARC dissident groups,” who are still fighting, said Adam Isacson, a Colombia expert at the Washington Office on Latin America, in reply to written questions.

The FARC converted into a legal political party last year, and won 0.3 percent of the vote in congressional elections last month. Presidential candidate Ivan Duque, who campaigned against the peace accord with the FARC, is leading in polls ahead of the May 27 election.

Today’s move may weaken Duque’s argument that the Santos government is handing over the country to the FARC, Isacson said.

Santrich is sought by the U.S. District Court Southern District of New York, and faces a maximum of life imprisonment in found guilty, according to documents sent by the presidency.