The outcry grew in Russia over the crackdown on peaceful protesters Thursday as EU foreign policy chief Josep Borrell was set to visit the country under pressure to confront Moscow over the imprisonment of opposition figure Alexei Navalny.

Borrell's visit -- the first to Russia by a top EU envoy since 2017 -- comes at a period of unusual turbulence in the country, with tens of thousands taking to the streets in support of President Vladimir Putin's top critic.

Navalny was sentenced this week to nearly three years in prison.

Over the past few weeks police detained thousands of protesters and dozens of journalists, and detention centres in Moscow and Saint Petersburg were overflowing with demonstrators serving brief jail terms. 

On the eve of the EU foreign policy chief's visit, a court sentenced Sergei Smirnov, chief editor of Mediazona -- an online news publication often critical of the government -- to 25 days in jail over a re-tweet of a joke that included the time of a recent protest rally.

The jailing of Navalny, 44, and the crackdown sparked outrage among many Russians, and top broadsheets added their voices to the chorus of condemnation.

"Over the past few weeks we've witnessed extremely harsh actions of members of law enforcement," leading broadsheet Kommersant said. "Beatings and mass detentions should not become the norm in our country."

Kommersant said Smirnov's arrest was an "attempt to intimidate" both Mediazona and other media.

Business daily RBC said several of its journalists had witnessed "detentions and the use of force" against the media during the protests. The newspaper demanded that law enforcement publicly explain the arrest of Smirnov and other journalists.

Monitors say at least 10,000 people have been detained at the nationwide demonstrations.

Navalny's allies called on Russians to take to the streets after he was detained last month on arrival from Germany where he had been recovering from nerve agent poisoning.

Clear messages

Borrell is eager to sound out Russian Foreign Minister Sergei Lavrov on the chances of cooperation on issues including enlisting Russia's help in reviving the Iran nuclear deal and tackling climate change. 

But the jailing of Navalny and the police crackdown are expected to dominate the agenda.

Borrell's visit has drawn criticism from some European capitals worried Moscow will spin it as evidence Brussels is keen to return to business as usual.  

Borrell insists he will deliver "clear messages" to Moscow despite it blanking Western calls to free Navalny who has accused Putin of trying to kill him.

"It is when things are not going well that you must engage," the former Spanish foreign minister said on Monday. 

The EU's ties with Russia have been in the doldrums since Moscow seized Crimea in 2014 and fuelled a war in Ukraine that claimed more than 13,000 lives. 

There are also concerns about Russia's involvement in Belarus, Syria, Libya, the central Africa and the Caucasus.

No repression

On Thursday, Putin's spokesman Dmitry Peskov said Brussels and Moscow should be able to freely discuss "all existing differences".

"We would like to unblock our dialogue," he said.

He reiterated Kremlin support for the police response, insisting demonstrations have not been authorised.

"There is no repression whatsoever," he added.

Kremlin critics say there's a concerted effort to intimidate dissenters, dismantle Navalny's Anti-Corruption Foundation and put pressure on the opposition's family and allies.

In Europe calls are growing for the EU to bulk up on sanctions it slapped on six Russian officials in October over the nerve agent poisoning that left Navalny fighting for his life in a German hospital.

EU foreign ministers last week agreed they would revisit the issue if he was not released. 

An EU statement said foreign ministers would discuss "possible further action" at a meeting on February 22. 

Navalny himself called for sanctions to hit the oligarchs and money-men he accuses of protecting Putin's wealth. 

But European diplomats say that any measures, if they come, would likely just target officials and functionaries directly involved in the clampdown.