A Russian blogger was told Tuesday that he is under criminal investigation for inciting riots with comments on demonstrations against Vladimir Putin, raising fears that the authorities intend to restrict the Internet, where the protest movement was inspired and organized.

The Internet here has been robust and free so far, in contrast to television, the source of most Russians’ information and the conduit for what officials ensure is a relentlessly pro-Putin message. Most of the big newspapers are in hands sympathetic to or fearful of the Kremlin, and only a few small newspapers and Internet TV stations offer opposing viewpoints. Though other bloggers have not reported trouble with the police yet, they see this case as a warning to them all.

“It’s like 1937,” said the accused blogger, Arkady Babchenko, referring to the days of Stalinist repression and show trials. “It’s obvious this is a political case.”

Oleg Kozyrev, an influential blogger, said the action against Babchenko echoes methods favored by Putin, who won the presidency March 4 in an election that was widely perceived as unfair and prolonged the protests that began in December after disputed parliamentary elections.

“His whole approach is based on show trials,” Kozyrev said, recalling the case of former oil tycoon Mikhail Khodorkovsky, who has been in prison since 2003 and whose prosecution was interpreted as a warning to other powerful businessmen to avoid challenging Putin. “I don’t expect mass trials of journalists and bloggers, but just enough to frighten them,” Kozyrev said.

The complaint against Babchenko was brought by Boris Yakemenko, a political operative with close Kremlin ties. No evidence has been disclosed of any involvement by Putin, who is currently prime minister, but his acolytes often act in ways they think will please him.

Yakemenko accused Babchenko of calling on protesters to barrel through police lines with a snow plow and occupy Lubyanka Square, in front of the building housing the security services.

In that posting of Feb. 27, Babchenko discusses such action but argues that it would do little to advance the opposition cause of holding new parliamentary elections and removing Putin from office. What the opposition should do, he wrote, is organize in cities and towns across the country. “All these actions are very peaceful,” he blogged, “but they can mean pressure on the authorities and a complete change of the regime.”

Yakemenko is known here for helping to organize and groom a pro-Kremlin youth movement called Nashi, which means Ours. He has previously been accused of paying bloggers to post pro-Kremlin comments. Reached by telephone Tuesday, he declined to comment on the case.

If convicted, Babchenko, a 35-year-old former soldier who made a reputation as a war correspondent, could face two years in prison. Prosecutors said that in addition to pursuing Yakemenko’s accusation against him, they would also probe other alleged violations.

Georgy Bovt, a journalist and political analyst, said he did not think the case was strong enough for a criminal conviction but could result in a fine after many months of legal struggle. He said it was too early to tell whether the action went beyond the initiative of Yakemenko, a powerful member of the elite.

But there have been signs recently of a broader impatience with dissent, including a prison term for the husband of an opposition organizer, harsh treatment and jailing of members of a feminist punk band who performed an anti-Putin song in Moscow’s main cathedral, the arrest of environmentalists in the Krasnodar region and growing intolerance of demonstrations — recent ones have been unsanctioned and protesters arrested.

Bovt said he expects targeted reprisals once Putin is inaugurated May 7. Leaders of the opposition may find themselves in trouble, along with disloyal media, he said.

“There will be individual circumstances,” he predicted, “criminal investigation for one, tax violations for another, ethical breaches, financial problems, whatever. They’ll be adjusted to the particular target.”

Babchenko is convinced the reprisals have now begun.

“They want me in jail,” he said. “They want to shut me up.”