By Gabrielle T’trault-Farber and Barbara Goldberg

MOSCOW/NEW YORK (Reuters) – A retired U.S. Marine who has been detained by Russia for alleged spying was visiting Moscow for the wedding of a former fellow marine and is innocent of the espionage charges against him, his family said.

Paul Whelan had been staying with the wedding party at Moscow’s Metropol hotel when he went missing, his brother, David, said.

“His innocence is undoubted and we trust that his rights will be respected,” Whelan’s family said in a statement released on Twitter on Tuesday.

Russia’s FSB state security service said Whelan had been detained on Friday, but it gave no details of his alleged espionage activities. Espionage can carry a prison sentence of between 10 and 20 years under Russian law.

A U.S. State Department representative said Russia had notified it that a U.S. citizen had been detained and it expected Moscow to allow consular access to him.

“Russia’s obligations under the Vienna Convention require them to provide consular access. We have requested this access and expect Russian authorities to provide it,” the representative said, without providing details of the American’s identity or the reasons behind his detention.

David Whelan told CNN that his brother, who had served in Iraq, has been to Russia many times in the past for both work and personal trips, and had been serving as a tour guide for some of the wedding guests. He apparently disappeared on Friday and his friends filed a missing persons report in Moscow, his brother said.

David Whelan told the news channel that the family was relieved at first when they heard he was in custody.

“It’s knowing that he’s not dead, it weirdly really helps,” he said.

He declined to comment on his brother’s work status at the time of his arrest and whether his brother lived in Novi, Michigan, as address records indicate.

BorgWarner, a Michigan-based automotive parts supplier, said Whelan is the “company’s director, global security. He is responsible for overseeing security at our facilities in Auburn Hills, Michigan and at other company locations around the world.”

BUTINA CASE

Daniel Hoffman, a former CIA Moscow station chief, said it was “possible, even likely” that Russian President Vladimir Putin had ordered Whelan’s arrest to set up an exchange for Maria Butina, a Russian citizen who pleaded guilty on Dec. 13 to acting as an agent tasked with influencing U.S. conservative groups.

Russia says Butina was forced to make a false confession about being a Russian agent.

Putin’s aim was “to make us feel some pain and his family to feel some pain. That’s their (Moscow’s) pressure point,” Hoffman told Reuters.

“Putin knows there will be a lot of public square pressure to get this guy out,” he said.

Putin told U.S. President Donald Trump in a letter on Sunday that Moscow was ready for dialogue on a “wide-ranging agenda,” the Kremlin said following a series of failed attempts to hold a new summit.

At the end of November, Trump abruptly canceled a planned meeting with Putin on the sidelines of a G20 summit in Argentina, citing tensions about Russian forces opening fire on Ukrainian navy boats and then seizing them.

Trump’s relations with Putin have been under a microscope as a result of U.S. Special Counsel Robert Mueller’s investigation into alleged Russian meddling in the 2016 U.S. election and possible collusion with the Trump campaign.

Moscow has denied intervening in the election and Trump has branded Mueller’s probe as a witch hunt.

Russia’s relations with the United States plummeted when Moscow annexed the Crimean peninsula from Ukraine in 2014, and Washington and Western allies have imposed a broad range of sanctions on Russian officials, companies and banks.

(Reporting by Barbara Goldberg in New YorkAdditional reporting by Jonathan Landay in Washington and Rich McKay in Atlanta, Editing by Bill Tarrant, Paul Simao, Richard Balmforth)