MOSCOW: Russian police detained top allies of Alexei Navalny at a Moscow airport on Sunday as the Kremlin critic was flying home from Germany under threat of imminent arrest.

Navalny was returning to Russia for the first time since a near-fatal poisoning in August, in defiance of warnings from officials that they would arrest him for breaking the terms of a suspended prison sentence.

Supporters had gathered at Moscow's Vnukovo airport, where his plane was due to land around 7:30 pm (1630 GMT), despite the airport banning mass events because of coronavirus restrictions.

With his plane still in the air, police detained top aides including prominent Moscow activist Lyubov Sobol.

Footage shot by local journalists showed police leading her and three others away, while there were reports of at least 10 people detained.

The flight carrying Navalny from Germany, where the 44-year-old spent months recovering from the August poisoning, took off from Berlin's Brandenburg Airport just after 3:15 pm (1415 GMT), according to AFP journalists on the plane.

Wearing a blue face mask, green jacket and scarf, Navalny boarded with his wife Yulia.

Speaking to reporters on the plane, he said he did not fear being arrested on arrival in Moscow.

"They will arrest me? They will arrest me? That's impossible, I'm an innocent person," Navalny said.

"I feel I am a citizen of Russia who has the full right to return to his home."

There was a heavy security presence at Vnukovo, AFP journalists at the airport said, including dozens of police in riot gear with black helmets and batons.

Some Navalny supporters had also gathered, including Tanya Shchukina, an artist who had travelled from Saint Petersburg.