U.S. says began mulling spy swap as early as June 11

WASHINGTON (Reuters) - Back when President Barack Obama sat eye-to-eye eating hamburgers with Russian President Dmitry Medvedev on June 24, he had a secret.

Obama had been told nearly two weeks earlier -- on June 11 -- about a suspected Russian spy ring operating in the United States, a White House official said on Friday.

The Russians were arrested on June 27 and the idea of swapping the 10 Russians for alleged spies held by Moscow was raised before the arrests were made.

The White House official, speaking on condition of anonymity, said Obama had been given extensive details at the June 11 Oval Office meeting about the individuals involved and what they were accused of doing over the past decade.

He was told that some of the Russians had plans to travel abroad this summer.

It was at this meeting that the idea of swapping the Russians came up, well before they were ever arrested. Other options were also discussed.

Obama chaired a meeting of the National Security Council on June 18 to discuss the spy case.

Details on the prelude to the biggest U.S.-Russia spy exchange since the Cold War were released hours after the two countries traded agents on the tarmac at Vienna's airport on Friday.

U.S. law enforcement agencies first briefed White House officials in February about long-running surveillance of the Russians' undercover activities, the official said.

The U.S. government came up with the four individuals to be released by the Russians based on humanitarian concerns, health concerns and other reasons that were put forward to the Russians. CIA Director Leon Panetta led the conversations.

"These names were put to the Russians within days of the arrests," said the official. "And we received a response soon after the names were offered."

The dramatic conclusion to the espionage scandal came after spymasters brokered the deal with the approval of Obama and Medvedev, both keen not to derail improving relations between their countries.

(Reporting by Matt Spetalnick and Steve Holland; Editing by Paul Simao)