The agency had suggested that John Edward Tobin, a 24-year-old native of Ridgefield, Conn., had U.S. intelligence training. It said his arrest showed that potential spies could be found even under cover of exchange students.
But a spokesman for the Federal Security Service, known by its Russian acronym FSB, stressed on Wednesday that Tobin faced only drug charges.
"He didn't ever carry out any spying activity on Russian territory. We don't have any claims on him," said Pavel Bolshunov, an FSB spokesman in Voronezh, the central Russian city where Tobin has been jailed.
"The political information which Tobbin was collecting was fully in line with his dissertation and does not harm the interests of Russia," he said.
Tobin was detained at a nightclub on Jan. 26, and was formally arrested on Feb. 1 for possession of 4.5 grams of marijuana. But Bolshunov said Wednesday that Tobin might also be charged with distributing marijuana.
Under Russian law, this could mean either selling the drug or offering it free to friends. Tobin faces three years in prison if he is convicted of possession and seven if he is convicted of distributing marijuana.
"The bags of narcotics were small, but by our laws it was enough to open a criminal case. This is not Holland, we have strict laws," Bolshunov said.
Bolshunov said the FSB "allowed itself to comment on the case," which he described as "small," because it found Tobin's alleged background as a U.S. army soldier trained in Russian language and interrogation suspicious. He said Tuesday that the FSB believed Tobin was an interrogation specialist who had been sent to Russia for additional country and language training.
Tobin, a Fulbright scholar, was doing research for a political science thesis on Russia's transition to democracy at the Voronezh State University, 300 miles south of Moscow.
Bolshunov said it was an embarrassment that the alleged U.S. agent-in-training was caught apparently smoking marijuana while on a study assignment in a foreign country.
"He discredited very serious institutions that might stand behind him," Bolshunov said.
Pavel Felgenhauer, an independent security and defense analyst in Moscow, said the suggestion of espionage links was a warning for foreign organizations working in Russia, such as the Fulbright exchange program.
"Those who sent him can be accused of being accomplices in spying activity, even if they have no access to secret information," he said. He said the arrest reflected anti-American sentiment among midlevel officials in Russia's security establishment.
Tobbin was seen saying on an official video tape of the search of his apartment that some of the rugs had been planted on him.
Russian-U.S. ties have been overshadowed in recent months by spying rows. Last week, FBI officer Robert Hanssen was arrested on charges of spying for Moscow for 15 years.
The State Department official rejected any link between Tobin's case and those of Hanssen or of Edmond Pope, sentenced to 20 years for spying and pardoned in December by President Vladimir Putin.
"The Fulbright program is not a training ground for spies," the official said, reading from prepared comments.
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