Russian authorities detained a U.S. citizen and accused him of espionage, Russian domestic intelligence agency FSB said in a statement Monday.

Paul Whelan was arrested while “carrying out spying activities” Dec. 28, according to the FSB statement cited by The Wall Street Journal.

Whelan could be punished with 10 to 20 years in jail, according to Russian news agency TASS.

The State Department was formally notified of the U.S. citizen’s detention and expects Russia to provide consular access to the citizen because of the Vienna Convention, a department spokesperson told The Daily Caller News Foundation via email Monday.

News of the detention comes shortly after Russian President Vladimir Putin said Russia is “open to dialogue” with the U.S. in a holiday message to President Donald Trump on Sunday.

Putin discussed meeting with Trump as recently as Dec. 20.

“I don’t know whether a meeting will happen,” Putin said during a press conference, according to CNN. “On multiple occasions, I’ve said I am willing to meet. We have a number of issues to discuss including our bilateral agenda.”

Meanwhile, the U.S. government has sanctioned Russia’s FSB for its cyber activities even though FSB and U.S. intelligence agencies cooperate on counterterrorism activities, reported CNN. The FSB evolved from the infamous Soviet security agency the KGB.