A suspect in the Russia spy case has confessed after his arrest that he was a Russian agent operating under a false identity, a U.S. prosecutor said Thursday.

The suspect, a resident of Yonkers, New York, confessed that Juan Lazaro was not his true name, and that he was not Uruguayan, Attorney Preet Bharara said in a letter to Judge Ronald Ellis of a federal court in Manhattan.

Russia-U.S. spy scandal

But Lazaro did not reveal his true name, telling investigators that he would not violate his loyalty to Russian secret service "although he loved his son."

The suspect also confessed that his wife Vicky Pelaez, a Peruvian journalist, went to South America several times to pass intelligence to other agents, the prosecutor said in the letter.

Lazaro and Pelaez are among 11 suspects charged with gathering intelligence in the United States for Moscow, in a spy case that has made headlines and risks harming U.S.-Russian ties at a time when the two countries were making efforts to "reset" relations.

The U.S. Justice Department announced the arrest on Monday. Ten of the suspects were arrested in four eastern cities. Another suspect arrested in Cyprus on Tuesday and freed on bail, apparently went missing, prompting the U.S. prosecutor to send a letter to urge Ellis not to make the same mistake.

The ten suspects arrested in the United States appeared in three separate courts on Thursday. Ellis decided that Pelaez could be bailed on a bond of 250,000 U.S. dollars and put under house arrest.

"Vicky's case is more complicated, she does not appear to be a trained agent. She has a real identity and she is a U.S. citizen," he said.

The judge said he would decide on Lazaro's bail later. He ordered two other suspects Richard and Cynthia Murphy to be held.

Another suspect, Anna Chapman, had her bail request rejected by Ellis on Monday.

The bail hearings of the other five suspects in Boston and Virginia were postponed.

The White House said President Barack Obama knew about the FBI operation on the spy case before meeting Russian President Dmitry Medvedev last week.

Russian Foreign Ministry had acknowledged in a statement on Tuesday that some of the suspects involved in the spy case were Russian citizens, but denied that the suspects acted against U.S. interests.

Russia at first had said the U.S. actions were "unfounded," but later said it hoped the spy case will not harm bilateral relations and that it was ready to assist Russian nationals accused of spying.