Russia has allowed consular access to a retired U.S. Marine who has been detained on espionage charges, the country's foreign ministry said Wednesday.
Access was granted just hours after U.S. Secretary of State Mike Pompeo said he expected an explanation about why the American was arrested and demanded his release if the detention is not appropriate.
On Monday, Russian Federal Security Service (FSB) officials said the American, who has been identified as 48-year-old Paul Whelan, had been detained Dec. 28 "while carrying out an act of espionage," and a criminal probe has been ordered.
They provided no further details, but Russia's state-run TASS news agency said Whelan faces up to 20 years in prison if convicted.
Whelan is employed as director of global security at BorgWarner, an American automotive parts supplier.
Whelan's family learned of his arrest only after it was reported by Russian state news outlets, prompting the family to contact congressional representatives and U.S. diplomats.
"We are deeply concerned for his safety and well-being," the family said. "His innocence is undoubted and we trust that his rights will be respected."
Whelan's arrest coincides with several spy scandals that have exacerbated tensions between Russia and the West, including the poisoning of former double agent Sergei Skripal and his daughter in Britain.
Russian citizen Maria Butina was convicted in the U.S. recently for acting as an illegal foreign agent. Butina pleaded guilty to acting under the direction of a Russian official to establish relationships with influential Americans.
News of Whelan's detention came less than 24 hours after Russian President Vladimir Putin issued a New Year's greeting to U.S. President Donald Trump in which he said Moscow is amenable to a continuing dialogue with Washington on a range of topics.
In 2016, Izvestia, a Kremlin-aligned news outlet, reported there were 13 U.S. citizens in Russian jails at the time. The Kremlin has not since published any details on other Americans currently in Russian detention.
Pete Cobus in Moscow contributed to this report.