Alexei Navalny and his wife Yulia are seen at the passport control point at Moscow's Sheremetyevo airport. AFP

Kremlin critic Alexei Navalny was detained by Russian police at passport control late on Sunday after flying back to Russia from Germany for the first time since being poisoned last summer, a Reuters witness said.

Russia's FSIN prison authority confirmed that officers had detained the prominent critic of President Vladimir Putin, the Interfax news agency reported.

The prison service said he was detained for multiple violations of parole and terms of a suspended prison sentence and would be held in custody until a court makes a decision in his case.

Navalny, who is President Vladimir Putin’s most prominent and determined foe, had spent the previous five months in Germany recovering from a nerve agent attack that he blamed on the Kremlin. Navalny decided to leave Berlin of his own free will and wasn’t under any apparent pressure to leave from Germany.

The prison service made the announcement after the flight carrying Navalny landed in the Russian capital, though at a different airport than had been scheduled. It was a possible attempt to outwit journalists and supporters who wanted to witness Navalny's return.

Russia’s prison service last week issued a warrant for his arrest, saying he had violated the terms of suspended sentence he received on a 2014 conviction for embezzlement. The prison service has asked a Moscow court to turn Navalny’s 3 1/2-year suspended sentence into a real one.

After boarding the Moscow flight in Berlin on Sunday, Navalny said of the prospect of arrest: "It’s impossible; I’m an innocent man.”

The Kremlin has repeatedly denied a role in the opposition leader’s poisoning.
Navalny supporters and journalists had come to Moscow's Vnukovo Airport, where the plane was scheduled to land, but it ended up touching down at Sheremetyevo airport, about 40 kilometers (25 miles) away. There was no immediate explanation for the flight diversion.

Agencies