UPDATE 1-Russia extends detention of ex-U.S. marine accused of spying

A Russian court on Friday ruled that Paul Whelan, a former U.S. marine accused of spying, should be held in a pre-trial detention facility for a further three months to give investigators more time to look into his case. Whelan, who holds U.S., British, Canadian and Irish passports, was detained in a Moscow hotel room on Dec. 28 and accused of espionage, a charge he denies. If found guilty, he could be imprisoned for up to 20 years.

Russia's Federal Security Service detained Whelan after an unidentified individual handed him a thumb drive containing classified information. Whelan's lawyer has said his client believed he was being handed holiday snaps. The case has put further strain on already poor U.S.-Russia relations as has that of another detained American, private equity chief Michael Calvey.

The court on Friday said Whelan would be held in pre-trial detention until May 28, extending an earlier ruling to keep him in custody until Feb. 28. The U.S. embassy in Moscow said a consular official had visited Whelan in custody on Thursday.

It said, however, that it was unable to provide further information as Whelan had not been allowed by investigators to sign a privacy act waiver (PAW) that would legally allow the U.S. government to release information about the case. "In every other instance, we have been able to obtain a signed PAW, but in Mr. Whelan’s case, the Investigative Committee is not allowing this to happen. Why is this case any different?" embassy spokeswoman Andrea Kalan wrote on Twitter. (Additional reporting by Maria Tsvetkova and Maxim Rodionov; editing by Andrew Osborn)