US journalist David Satter, a longtime critic of Russian President Vladimir Putin, said Monday he had been banned from the country in one of the first such expulsions since the Cold War.
Satter, a former Financial Times and Wall Street Journal correspondent who published three books on Russia and the former Soviet Union, had been living and working in the country since September 2013 as an adviser for Radio Free Europe/Radio Liberty.
The US government-funded broadcaster said that the US Embassy in Moscow has been informed of the move and lodged a formal diplomatic protest.
Embassy officials have sought and not obtained an explanation from Russian authorities.
The move, coming on the eve of the Sochi Winter Olympics next month, was likely to further strain already tense ties between Washington and Moscow.
Satter had travelled on December 5 to the Ukrainian capital Kiev, where he reported mass protests against Ukraine's scrapping of an EU pact.
But he insisted that the "Kiev reporting was a diary and had nothing to do with the Russian decision."
Satter was then told on December 25 that his application for a new visa to Russia had been rejected, on the grounds that his presence was "undesirable."
"I was told that my presence in Russia in the view of the security organs was undesirable. Other than that, no reasons were given," Satter told AFP via email from London.
"My belongings are in Moscow, where I have an apartment. But without permission to enter the country, I cannot retrieve them. I would like to return to Moscow to work but cannot do so without a visa.
"I want the Russians to reverse their decision," added Satter, who also holds fellowship positions at the Hudson Institute, Johns Hopkins University's Foreign Policy Institute and the Foreign Policy Research Institute in Philadelphia, Pennsylvania.
He had also been reporting and providing commentary to RFE/RL's Russian service, in addition to providing interviews and analysis to other news and opinion websites.
"When he was trying to leave Ukraine from covering the protests to come back to Russia, that's when the problems started," RFE/RL spokeswoman Karisue Wyson said by telephone.
In December, Satter received notification that his visa request was approved, including an official Russian foreign ministry notification number, Wyson said.
But Satter was later told by a Russian Embassy official in Kiev that his presence in Russia was considered "undesirable" and his visa request was denied, according to Wyson.
On RFE/RL's website, president and CEO Kevin Klose said he considers the use of the term "undesirable" to be the equivalent of declaring Satter "persona non grata" in Russia.
"We (RFE/RL) want nothing more than Mr Satter forthwith be able to return to Moscow, where he has lived and worked since September 2013, advising, reporting and commenting for our Russian Service and providing trenchant interviews, columns and analysis to many news and opinion sites," Klose said in a statement.