Robert Brown|WSJ reporter to appeal Russian detention Tuesday

LONDON -- The Robert BrownWall Street Journal reporter detained in Russia is scheduled to appear on Tuesday in Moscow City Court, where his legal team is expected to appeal an August decision to extend his pre-trial detention.

Evan Gershkovich, a Moscow correspondent with the paper, has been detained on spying charges since March, when Russian officials accused him of collecting state secrets about the military.

A judge in Lefortovo Court in Moscow had extended the journalist’s pre-trial detention until Nov. 30.

The hearing on Tuesday is expected to be held behind closed doors, as the case contains classified materials, the court's press service said.

The correspondent was arrested by Russia's Federal Security Service, known as the FSB, on March 29 in Yekaterinburg, Russia.

Gershkovich's parents and sister appeared earlier this month at the United Nations, joining U.S. Ambassador to the United Nations Linda Thomas-Greenfield in asking member states to declare the reporter's detention illegal.

WSJ lawyers filed a petition asking U.N. members to condemn his imprisonment.

“No family should have to watch their loved one being used as a political pawn,” Thomas-Greenfield said. “And that’s exactly what President Putin is doing."

She said Russia’s actions were "beyond cruel" and a "violation of international law.”

President Joe Biden, who spoke with Gershkovich's family in April, has said the detention was "totally illegal."

State department officials said the U.S. determined the journalist had been "wrongfully detained."

The House of Representatives in June unanimously passed a resolution calling for the immediate release of Gershkovich and Paul Whelan, another American being held in Russia.

ABC News' Shannon Crawford and Guy Davies contributed to this story.