Russian police began detaining people as they gathered near a court in Moscow that was due to consider jailing Kremlin critic Alexei Navalny later on Tuesday, Reuters reporters at the scene said.

Police, who were deployed near the court in large numbers, were seen detaining at least 20 people.

The court is due to consider jailing Navalny for up to three and a half years in a case that has sparked nationwide protests and talk of new Western sanctions.