The Russian Foreign Ministry said the US has detained a Russian citizen on Saturday, a week after Moscow arrested a former US marine on suspicion of spying.
The American Paul Whelan was detained by Russia's Federal Security Service on December 28.
His family protest he is innocent of the espionage allegations and that he was in Moscow to attend a wedding.
Russia's ministry said on Saturday the US detained Russian citizen Dmitry Makarenko on the Northern Mariana Islands on December 29 and had moved him to Florida.
"... Makarenko, born in 1979, has arrived on Saipan Island with his wife, underage children and elderly parents. He was detained by FBI personnel at the airport right after his arrival," the ministry said.
The allegations could complicate an already strained relationship between the two nations.
US Secretary of State Mike Pompeo said this week Washington had asked Moscow for more information on the charges Whelan faces.
While the UK, a country which Whelan also holds a passport for, warned Russia that individuals should not be used as diplomatic pawns. The former marine also holds an Irish passport.
Before Moscow gave details of the recent alleged arrest of its citizen, experts had rumored that Moscow could exchange Whelan for Russian nationals held by Washington.
Russia's Interfax news agency quoted Deputy Foreign Minister Sergei Ryabkov as saying: "I see no reasons to raise this issue in context of exchanges. We should undergo all the procedures needed in this situation".