A federal grand jury indicted a snack shop owner Tuesday for failing to tell the government he was working as an agent for North Korea, officials said.

Prosecutor Daniel Goodman said there is evidence John Joungwoong Yai was told to get top-secret information and tried to recruit agents for North Korea who could be used as "moles" in government agencies.

He was not charged with espionage because no evidence was found showing he was successful in obtaining or passing classified documents, authorities have said.

Yai's attorney, William Genego, says the government closely monitored his client for seven years but came up with nothing to suggest he is a spy.

Yai, 59, is a South Korea native who moved to the United States in 1975 and became a naturalized citizen. He was arrested Feb. 4.

Federal law requires people to register with the U.S. Department of Justice if they represent a foreign government but are not diplomats or involved in a legal commercial enterprise.

Yai also is charged with making a false statement to U.S. Customs agents and conspiracy for allegedly failing to declare $18,179 in cash when he and his wife returned from an overseas trip in 2000.

He faces up to 20 years in prison if convicted on all counts.

Yai was being held without bail pending a Monday arraignment.