MOSCOW - The Kremlin said on Thursday complete silence was needed when it came to discussions about possible prisoner exchanges involving Evan Gershkovich, a Wall Street Journal reporter arrested in Russia a year ago on suspicion of espionage.

Gershkovich, 32, became the first U.S. journalist arrested on spying charges in Russia since the Cold War when he was detained by the Federal Security Service (FSB) on March 29.

The reporter, the Journal and the U.S. government all deny he is a spy. Russia says he was caught red-handed.

Asked about when a court would hear Gershkovich's case or whether there would be a prisoner exchange, Kremlin spokesman Dmitry Peskov told reporters: "We do not have information about the court - it is not our prerogative."

"As for exchange matters, we have repeatedly stressed that there are certain contacts, but they must be carried out in absolute silence," Peskov said, adding that public remarks were a hindrance.

The FSB, the main successor to the Soviet-era KGB, said Gershkovich had been trying to obtain military secrets.

He has now spent almost a year at Moscow's high-security Lefortovo prison, which is closely associated with the FSB, and his detention has been extended to June 30. REUTERS