MOSCOW — Accelerating the Kremlin’s campaign against the country’s fledgling opposition, Russian investigators charged the blogger and anticorruption activist Aleksei Navalny on Tuesday with embezzlement, a crime that carries a sentence of up to 10 years. A previous case against him based on the same events was closed this spring in Kirov by prosecutors who said they had not found evidence of wrongdoing.

If the case progresses to an arrest or a sentence, it will signal a shift in strategy by President Vladimir V. Putin. For the 12 years he has served as Russia’s paramount leader, he has mainly refrained from criminal prosecutions of activist leaders, instead sidelining them with softer methods like short-term detentions and limited access to mass media. But some commentators say they expect to see more criminal cases brought against activists.

“A political decision has been made, though I don’t know for how long,” said Gleb Pavlovsky, a former Kremlin political consultant. “Maybe the people who made this decision think it is a short period of intimidation, which will be followed by a return to more velvet methods. But now there is a regime in which, given a range of choices, they are selecting the harshest.

“The system is informing us that it is changing the rules,” he said.

Mr. Navalny, 36, rose to prominence as a protest leader in large part because of his popular blog and Twitter feed, which he has used to report corruption and inside dealing by Kremlin officials. Since 2010, he has faced the possibility of criminal charges related to a state-owned timber company called KirovLes, but the charges announced Tuesday were significantly more severe.