The American former Marine who is being held in Moscow on spying charges also holds British, Irish and Canadian citizenship, officials said. Britain's foreign secretary charged Friday that Russia is trying to use him as a pawn in its geopolitical games.
The news that Paul Whelan holds citizenship in four countries brings international pressure on Russia from several fronts. Britain, Ireland, and Canada have asked that their diplomats be allowed to visit him as well as the U.S. ambassador.
Whelan, the 48-year-old global security director for a U.S. auto parts company, was arrested Dec. 28 in Moscow. At the time, he was identified only as an American.
Russian authorities have released no information about the charges against Whelan, who could face up to 20 years in prison if convicted of spying. Russian media reported Thursday that Whelan had been formally indicted for spying. The Interfax news agency said he denied the allegation.
Whelan's family says he was in Russia to attend a friend's wedding. A Russian lawmaker, meanwhile, hinted Friday that the detainee could possibly be swapped for a Russian woman in the United States who has pleaded guilty to trying to influence U.S. politics.
Relations between Moscow and London have hit a low point in the wake of Britain's allegations that Russian military intelligence agents were behind the nerve-agent poisoning of a Russian former double agent and his daughter in the British city of Salisbury in March.
British Foreign Secretary Jeremy Hunt said his government was helping Whelan.
"We are giving him every support we that we can, but we don't agree with individuals being used in diplomatic chess games," Hunt said Friday on Sky News. "We are extremely worried about him and his family."
U.S. Ambassador Jon Huntsman Jr. met with Whelan earlier this week at Lefortovo Prison in Moscow.
"He has British citizenship. The British side has sent a request for a consular visit. Work on it is in progress," the Russian state news agency Tass cited Foreign Ministry spokeswoman Maria Zakharova as saying.
Ireland's Department of Foreign Affairs on Friday confirmed that Whelan also holds Irish citizenship and said it is requesting consular access, while Global Affairs Canada confirmed that it is providing consular assistance to Whelan and is asking Russian authorities for more information on his case.
Whelan's twin brother David said in a statement for the family that they were "very pleased to know that staff of the U.S. Embassy in Moscow have been given consular access to Paul and confirmed that he is safe."
He said the family's "focus remains on ensuring that Paul is safe, well treated, has a good lawyer, and is coming home." He urged both the U.S. Congress and the U.S. State Department to help get his brother freed.
Whelan's arrest came two weeks after Russian gun-rights activist Maria Butina pleaded guilty in the United States to conspiring to act as a foreign agent by trying to infiltrate conservative circles and the National Rifle Association to influence U.S. politics.
Butina has become a cause celebre for Russia — her face is the profile picture on the Foreign Ministry's Facebook page — and the timing of Whelan's arrest has led to suggestions that he is being seen as a potential swap for her.
A top member of Russia's parliament, foreign affairs committee deputy head Dmitry Novikov, on Friday appeared to suggest that was a possibility once the investigation into Whelan was completed.
"I think that we have to give our special services the opportunity to finalize things with the detainees. Then we will see," he said, according to the Interfax news agency.
U.K.-Russian relations were sharply damaged by the Salisbury nerve agent poisoning in March, for which Russia has angrily denied involvement.
The two Russian suspects identified by British authorities, who were spotted on security cameras in Salisbury on the day that former Russian spy Sergei Skripal and Yulia Skripal were poisoned, claim they were businessmen on a short holiday to see the city's famed cathedral.
Britain expelled 23 Russian diplomats in the case, and Russia sent home the same number. Many British allies made similar expulsions, with more than 150 Russian diplomats kicked out overall.
Whelan, a former staff sergeant with the Marines in Iraq, has visited Russia since at least 2007. He is the global security director for the Auburn Hills, Michigan-based BorgWarner, an auto parts supplier.
Katz reported from London. Rob Gillies in Toronto also contributed.