By Zach Howard

(Reuters) - A Puerto Rican nationalist on the run for almost 30 years admitted on Friday to his role in a $7 million armored car robbery in Connecticut in 1983, authorities said.

Norberto Gonzalez-Claudio, 67, pleaded guilty in U.S. District Court in Hartford to bank robbery conspiracy and foreign transportation of stolen money.

He was accused of targeting a Wells Fargo Armored Service Corp vehicle in West Hartford and using the money to fund a group seeking Puerto Rican independence from the United States, called Los Macheteros, or "the cane cutters."

Gonzalez-Claudio also admitted possessing a machine gun when he was arrested in Puerto Rico in May last year.

At the time of the robbery on September 12, 1983, news outlets reported it was the largest-ever cash robbery in the United States. Two bank guards were taken hostage, bound, and injected with an unknown substance, the FBI said. No one was killed.

Los Macheteros, also known as Boricua Popular Army, had a membership of about 5,700 and an unknown number of scattered supporters and sympathizers, according to a 2006 book.

If the court approves his plea deal, Gonzalez-Claudio will be sentenced on September 27 to five years in prison for the robbery and a concurrent 37 months for the gun possession.

In May 2010, his brother, Avelino, was sentenced to seven years in prison for his role in the robbery. Of the 19 defendants charged in the case, only one, Victor Manuel Gerena, remains a fugitive, and authorities are offering up to a $1 million reward for a tip leading to his arrest.

Kimberly Mertz, special agent in charge of the FBI in Connecticut, said the plea was the result of nearly 30 years of investigation by the FBI in Connecticut and Puerto Rico.

(Editing by Barbara Goldberg; Editing by Peter Cooney)