Paul Whelan, ex-Marine held as spy in Moscow, pleads for help from Trump Whelan says he is a victim of a setup by Russia's security services.

Moscow -- Paul Whelan, the former U.S. Marine held in Russia on espionage charges, on Thursday called on President Donald Trump to help free him, saying he is the victim of a “political kidnapping” by Russia’s security services.

Whelan made the statement in Moscow’s City Court, where his lawyers were appealing the latest extension of his pre-trial detention. He has been held in Moscow’s Lefortovo Prison since his arrest in late December while visiting the city for a friend’s wedding. Agents of Russia’s domestic intelligence agency, the FSB, detained him in his hotel room and accused him of spying.

Whelan has denied the charges and in court hearings has accused Russia of seizing him as a political pawn. In court on Thursday he appealed directly to Trump for help.

“Mr. President, we cannot keep America great unless we aggressively protect and defend Americans wherever they are in the world,” Whelan said in a prepared statement to journalists while speaking from inside a glass cage in the courtroom, flanked by a masked guard.

Whelan accused Russian authorities of violating his human rights and deliberately isolating him to pressure him. He said he had been denied consular access and prevented from receiving letters.

The judge rejected Whelan’s appeal, upholding his detention until mid-August.

“This decision is pre-ordained,” Whelan told reporters as the judge read out the sentence.

Whelan also holds Irish, British and Canadian citizenship and on Thursday he called on those countries’ governments to help.

Russia has still not made public the charges against Whelan. But his Russian lawyers have slowly released details, saying Whelan is the victim of a setup.

His lawyers say during that Whelan's December trip, a Russian friend gave Whelan a memory card that, unknown to him, held classified material. Immediately after Whelan received the card in his hotel room, they said, FSB agents burst in and arrested him. The friend, Whelan's lawyers said, also worked for Russia’s security services.

Whelan’s family has accused Russia of seizing Whelan as a hostage and has urged the U.S. government to help free him. Former U.S. intelligence officials have also said the case looks like a classic KGB-style frame-up.

It is unclear why Whelan would have been targeted. A self-described Russophile, he has visited Russia several times over the past decade, according to his family. He left the Marines in 2008 with a bad conduct discharge for attempted larceny and other charges.

In court Thursday, Whelan suggested for the first time that his arrest may be linked to his work, where he is a director of global security for the Michigan-based auto-parts supplier, BorgWarner.

Addressing his employer, Whelan said, “This situation is work-related,” and asked them to provide “maximum co-operation”.

Whelan’s family has also expressed concerns about his Russian lawyers. His chief lawyer, Vladimir Zherebenkov, has at times behaved oddly, praising investigators and repeating that his client is “fine” when Whelan himself has complained that his rights are being abused.

Olga Karlova, Whelan’s English-speaking Russian lawyer, told ABC News their access to Whelan was limited in part because defense lawyers' access to their clients is limited by a lottery system at the prison, in which lawyers pick a number from a black bag to determine who goes first -- sometimes resulting in no access at all.

The U.S. State Department has recently become increasingly vocal in criticizing Whelan’s detention, asking why Russia has still not provided any evidence in his case.

Whelan’s sister, Elizabeth Whelan, met with National Security Advisor John Bolton and other senior national security advisors at the White House last week. Afterward Bolton tweeted, “Russia has provided no evidence of wrongdoing.”

Trump is expected to meet with Vladimir Putin in Japan next week at the G20 summit, where he may be under pressure to bring up Whelan’s case with the Russian president.