Dominic Raab has urged Russia to release citizens “detained simply for expressing their dissent” after thousands were arrested during protests in support of jailed opposition leader Alexei Navalny.

The Foreign Secretary condemned the “indiscriminate and arbitrary” arrests as tens of thousands took to the streets across the country on Sunday.

A monitoring group put the number of arrests at more than 5,100, while some were beaten, in what is the largest public display of discontent in Russia in years.

Mr Raab said: “We condemn the Russian authorities’ indiscriminate and arbitrary arrest of peaceful protesters and journalists.

“The Russian Government must adhere to its international commitments to respect peaceful protest, and release citizens detained simply for expressing their dissent.”

Mr Navalny, one of President Vladimir Putin’s most vocal critics, was arrested on January 17 after returning from Germany, where he spent months recovering from a Novichok poisoning.

The anti-corruption investigator blames the Kremlin for targeting him with the nerve agent.

The UK imposed sanctions on six Russians, including the director of the Federal Security Service, who the Government holds responsible for the poisoning.

Mr Navalny’s team called for another protest to take place in Moscow on Tuesday, when he could be imprisoned for years during a court hearing.