Paul Whelan, an American who holds an Irish passport, has been in Russian custody for over six months.FreePaulWhelan.com

Paul Whelan is currently being held in Moscow on charges of espionage

Paul Whelan, an Irish passport holder who is currently being held in Russia on suspicion of spying, is appealing to American and Irish governments for help.

Read More: Irish passport holder charged with spying in Russia had materials containing "state secrets"

Reuters reports that Whelan, a former US Marine, holds American, British, Canadian, and Irish passports. A website supporting his release says: "Paul was born in Canada to British parents who are of Irish descent. In the early 1970s, he moved to the US and lived in Ann Arbor, Michigan with his family. 

In December 2018, Whelan was arrested in Moscow on charges of espionage, which he claims is an "absurd political kidnapping." Whelan's lawyers assert that he was framed when he was given a flash drive that he thought contained holiday photos, but actually contained classified information.

If found guilty, Whelan could face up to 20 years in a Russian prison.

Read More: Irish American charged with spying in Russia

On Thursday, Whelan spoke with reporters in Moscow during a hearing in which he was appealing the extension of his custody through August 29, an appeal that the court ultimately denied.

From inside a glass cage, Whelan said: “Mr. President (Trump), we cannot keep America great unless we aggressively protect and defend American citizens wherever they are in the world.”

“Please tweet your intent on this,” Whelan said, adding “I am asking the leaders and governments in Ottawa, Dublin, London, and Washington for their help and public statements of support.”

Read More: Irish ambassador calls on US Congress to consider effect on Ireland with Russian sanctions policy

ABC World News Tonight tweeted a video of Whelan’s comments on Thursday:

Paul's brother David Whelan also tweeted:

Whelan's family have been sharing updates on the Free Paul Whelan Twitter feed and website. They are appealing for donations to help with legal fees on their GoFundMe.