Moscow, Russia - The Wall Street Journal has published a handwritten letter from Evan Gershkovich, its correspondent imprisoned in Russia on charges of espionage.

"I want to say that I am not losing hope," he wrote in a note to his family in Philadelphia, which was received on Friday. "I read. I exercise. And I am trying to write. Maybe, finally, I am going to write something good."

The handwritten letter is dated April 5 and, according to the newspaper, is the first direct contact Gershkovich has had with his family since his arrest in Russia in late March.

The letter is written in Russian – the language Gershkovich speaks with his parents. They immigrated to the US from the Soviet Union in the late 1970s.

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"Mom, you unfortunately, for better or worse, prepared me well for jail food," the journalist wrote, according to the newspaper. The food reminded him of his childhood.

The reporter was arrested by Russia's FSB secret service in the city of Yekaterinburg.

If convicted, Gershkovich faces up to 20 years in prison.

The affair has put even more strain on the already tense relations between Washington and Moscow following Russia's invasion of Ukraine last year. The US has officially classified the arrest as unlawful.