MOSCOW: Nationwide protests over the jailing of Kremlin critic Alexei Navalny and a sweeping police crackdown have so far had little impact on Russia President Vladimir Putin's approval rating, a survey by independent pollster Levada showed on Thursday.

A court on Tuesday sentenced Navalny, a prominent Putin opponent, to three and a half years for parole violations he said were trumped up, ignoring calls from the West and protesters at home to release him.

The Levada Centre poll, conducted in the leadup to the sentencing, showed an overall 1% drop in approval of Putin to 64% from 65% in November among 1,616 adults in 50 regions, a relatively small sample of Russia's 145 million population.

Over the course of the year, his rating among younger respondents had dropped 17% to 51%, it said.

During the Jan 29-Feb 2 polling period, his supporters had been spurred on by more than 100 million views of an online video in which Navalny said Putin was the ultimate owner of an opulent palace on the Black Sea, an allegation he denies.

"The euphoria in the liberal community is clearly very exaggerated. The main mass of the population is responding inertly to all the events linked to Navalny," Lev Gudkov, director of the Moscow-based Levada pollster, told Reuters.

"It's got a bit worse among young people, but it practically hasn't changed for the main mass (of people)," he said of the rating.

Putin, 68, remained Russia's most trusted politician with a rating of 29%, five percentage points down from October, while that of Navalny, 44, rose to 5%, putting him in sixth place, Levada said.

The poll highlighted dissatisfaction with the authorities concentrated in the younger generations, with 48% of 18-24 year-olds saying the country was moving in the wrong direction.

Putin's approval rating hit a low last year during the first wave of the pandemic and its fallout, before recovering.

Gudkov said the public may not have digested the events surrounding Navalny, who was poisoned in Russia in August before recovering in Germany and dramatically returning last month despite a previously-announced threat of arrest.

The anti-corruption campaigner says Putin had tried to have him killed with a nerve agent. The Kremlin denies involvement and says it has seen no evidence he was poisoned.

Police have detained thousands of people at rallies over Navalny's jailing in recent weeks.

Courts have handed down short jail sentences - with a combined total of more than 6,300 days - to around 750 people for protest offences since the first Navalny rally on Jan. 23, the OVD-Info protest monitor said. They've also issued over 500 fines worth more than 6 million roubles ($79,400).

Navalny ally Lyubov Sobol was charged with breaching COVID-19 restrictions on Thursday for calling on people to join a nationwide protest last month. Navalny's brother Oleg was charged with a similar offence this week.

The Kremlin on Thursday rejected allegations of state repression and said people had been detained for taking part in illegal protests.