That's according to sources who told Reuters the measures could come as early as Tuesday.

Navalny fell ill on a flight in Siberia last August and was airlifted to Germany, where doctors concluded he had been poisoned with a nerve agent.

Navalny has accused Russian President Vladimir Putin of ordering his murder, but the Kremlin has denied any involvement.

If President Joe Biden goes ahead with the sanctions, it would mark a clear departure from their approach to Russia taken by his predecessor, Donald Trump, who left office in January, let last summer's instant pass without any punitive US action.

The State Department did not immediately respond to a request for comment on the possibility of sanctions.

One source said the U.

S action may be coordinated with sanctions.

The European Union is planning to apply.

Last month, EU foreign ministers agreed to target four officials close to Putin with asset freezes and travel bans.

Navalny returned to Russia in January and was immediately arrested.

He is currently serving a 2.5 year jail sentence for violating the terms of his parole for a 2014 fraud conviction.

On Sunday, it emerged he had been transferred to a penal colony outside Moscow known for its severe conditions.

Biden has called the jailing of Navalny politically motivated and has pledged to take a tougher approach to Moscow.

He said the US would no longer be quote rolling over in the face of aggressive action by Russia.