A Canadian-born former U.S. marine who has been kept behind bars in Russia on spying charges for the past six months appealed Thursday to U.S. President Donald Trump for help.

Paul Whelan, who was born in Ottawa, was arrested in a hotel room in Moscow at the end of December and charged with espionage, which carries up to 20 years in prison in Russia.    

Whelan, who holds British, Irish, U.S. and Canadian citizenship, appealed to Trump in a Moscow court to intervene in his case and “defend” him.  

“Mr. President, we cannot keep America great unless we aggressively protect American citizens wherever they are in the world,” Whelan said, reading out his statement.

“Mr. President, we cannot keep America great unless we aggressively protect American citizens wherever they are in the world.– Paul Whelan

Whelan denies any wrongdoing, and his lawyer said that his client was handed a flash drive that had classified information on it that he didn’t know about.    

Whelan’s detention was extended Thursday until late August.

Whelan, who has lived in the U.S. for more than two decades, has previously complained of poor conditions in the Moscow jail where he is being kept. He said Thursday that the conditions there have somewhat improved.

Officials aware of his plight

The office of Canadian Foreign Minister Chrystia Freeland has condemned Whelan’s detention, saying in a statement earlier this year that “detention should not be used as a political tool.”

Trump has arguably taken a greater interest in the cases of Americans held abroad than his recent predecessors, publicly advocating for, or commenting on, the release of U.S. citizens Serkan Golge and Andrew Brunson in Turkey, Danny Burch in Yemen and a number of Americans detained in North Korea.

But the president has yet to make substantive comments on Whelan’s case, stating in early January when asked by a reporter about the case, “we’re looking into that.”

It’s not clear if the subject will come up as Trump and Canadian Prime Minister Justin Trudeau meet later Thursday.

The case has drawn the attention of the two highest-profile members of Trump’s foreign relations team.

National security adviser John Bolton tweeted earlier this week that he had met with Whelan’s sister, Elizabeth, last week. Bolton castigated Russian officials for showing no evidence to support the charges.

U.S. Secretary of State Mike Pompeo, on a visit to Russia last month that included meetings with his counterpart Sergey Lavrov as well as President Vladimir Putin, said at a news conference in Moscow he had “raised the issue of U.S. citizens who have been detained in Russia.”

In early January, Pompeo said the U.S. would “demand his immediate return” if the charges Whelan was facing were found to be inappropriate.