San Francisco Frontiers - Russian court upholds extension of US reporter's detention: AFP

Gershkovich, whose arrest by Russia's FSB security services in late March sparked a global outcry, appeared in a glass cage in the Moscow court, and made a heart symbol with his hands to other journalists in the room.

"The court considered the complaint brought by Gershkovich's defence against the decision to extend his ... detention, and ruled that the initial decision should be left unchanged and the complaint of the defendant's defence should not be satisfied," the judge said.

Moscow says the sensitivity of the espionage charges means the trial must be held in private and court documents are not being made public.

Gershkovich, who previously worked for AFP, was the first foreign journalist arrested in Russia on spying charges since the collapse of the Soviet Union.

"We were extremely disappointed by the denial of his appeal," US ambassador to Russia Lynne Tracy said, addressing journalists outside Moscow City Court.

"Despite Russian officials' public assertions about Evan's activities, let me reiterate the US government's firm position: the charges against him are baseless," she added.

- 'Wrongfully detained' -

"He's an innocent journalist, who was carrying out journalistic activities and has been wrongfully detained".

She added that Russian authorities had denied three consular visits to Gershkovich, partly as the result of a visa disagreement with the United States involving Russian journalists.

Gershkovich's parents, who left the Soviet Union and emigrated to the United States, were both present in the courtroom, the AFP journalist reported.

They declined to speak to assembled reporters.

Gershkovich, a reporter for the Wall Street Journal, which vehemently denies the allegations against him, is being held at Moscow's Lefortovo prison.

The jail is notorious for keeping detainees in near-total solitude.

Q.Nelson--SFF