MOSCOW — Aleksei A. Navalny, the Kremlin’s most high-profile domestic critic, was released from jail on Friday after 30 days and said that opposition to President Vladimir V. Putin and protests against the authorities would grow despite efforts to crack down on the opposition.
Mr. Navalny, who has tried to garner popular support by exposing corruption in Russia, spoke just after completing a sentence for encouraging a protest calling for free elections.
“Now we see that lies and fraud are not enough for them. It’s not enough for them to ban candidates from an election. They deliberately want to arrest dozens and to beat up hundreds,” he said. “This shows that there is no support for this regime. They feel this and they are afraid.”
Decrying what he said were intimidation and terror directed at random people, Mr. Navalny said that the wave of protests would only intensify and that “this regime will seriously regret what it has done.”
Mr. Navalny, a 43-year-old lawyer and activist, was jailed last month after calling for Russians to demonstrate in central Moscow in response to the exclusion of opposition candidates from a local election in the capital next month.
The election, though it will select only city officials, is seen as a dry run for a national parliamentary election due in 2021.
The authorities’ refusal to register a slew of opposition candidates, including some of Mr. Navalny’s allies, on technical grounds has triggered the biggest sustained protest movement in Russia since 2011-2013, when protesters took to the streets against what many saw as electoral fraud.
Police have briefly detained over 2,000 people, opened criminal cases against around a dozen people for mass disorder, handed short jail terms to almost all of Mr. Navalny’s entourage and used force to disperse what they said were illegal protests.
Mr. Putin said this week that authorities were handling the situation in line with the law and that he did not want protests similar to those inspired by the “Yellow Vest” movement in France.
The governing United Russia party’s popularity rating is at its lowest level since 2011, and Mr. Putin’s personal rating has declined because of discontent over falling living standards.
However, at well over 60 percent, it is still high compared with those of many other world leaders. Mr. Putin, who first came to power in 1999 and is now 66, won re-election last year by a landslide to a six-year term that does not end until 2024.
On Friday, Mr. Navalny thanked people for taking to the streets and lauded what he said was the bravery of those opposition candidates excluded from the election.
“They are doing their best. And in them we see real new opposition,” he said. “And I am very happy about it.”