Anti-Kremlin blogger Alexei Navalny speaks to journalists and supporters outside a police station in Moscow, Russia, on December 21, 2011. (Andrey Smirnov/AFP/Getty Images)

The anti-corruption blogger Alexei Navalny, who is being investigated for his role in a demonstration in May that turned violent, tweeted this week that he was being followed by four unmarked police cars, instead of the usual two. Ten people, he wrote, were riding in them.

Maria Baronova, who was charged in connection with the same protest, then tweeted that she clearly wasn’t as big a deal, but that police were keeping a 24-hour watch on her apartment house.

And that inspired the underground artist Pyotr Verzilov to tweet that when he went to try to see his wife, a feminist punk rocker, in jail Tuesday morning, three cars followed him all the way.

The surveillance is one small measure of the resources that the authorities are willing to commit to fighting back against the political opposition here — although with one of the largest police forces in the world, Moscow may have manpower to spare.

“It’s more of a level of psychological pressure than an effective surveillance measure,” Verzilov said in a later interview. The followers make no effort to disguise what they’re doing; he believes it’s all about intimidation. Yet Verzilov, who is what might be called a guerrilla artist, is no stranger to police attention, and he doesn’t seem to take intimidation to heart. Neither does an activist like Navalny, boasting about his entourage.

Verzilov hasn’t seen his wife, Nadezhda Tolokonnikova, outside a courtroom since her arrest in early March, after a group of masked women staged a protest in Christ the Saviour Cathedral, singing a song asking for redemption from Vladimir Putin. The incident, and the protracted pretrial jailing of Tolokonnikova and two other members of her band, Pussy Riot, have become a major cause here among those who are shocked at the punitive treatment they have received, and at what seems to be the vindictive attitude of church leaders.

On Sunday, both the Red Hot Chili Peppers and Franz Ferdinand, playing separate concerts in Moscow, called for the release of the Russian punk rockers. Anthony Kiedis of the Red Hot Chili Peppers wore a T-shirt with the band’s name on it. On Friday, outside the Russian Embassy in Washington, Amnesty International plans to hold a rally and concert in support of the group.

The three band members are accused of hooliganism. They say they are innocent — and that the stunt was pulled off by others. Their trial is now scheduled to begin Monday. It could last one day, or 10 or 15, Verzilov said. “Nobody knows for how long.” They face sentences of as much as seven years in prison.

He said his effort to see his wife Tuesday came to nothing in the end, after nearly five hours. Having finally received permission from the court to see her, he arrived at 6 a.m., he said, and waited in line for three hours. Finally he was registered and admitted, and once inside the jail, he waited for almost another two hours. Then, he said, a staff member came out and told him, and others with him, that the young women had been taken to court to read the charges against them. “So they’re not here.”

Verzilov chalked it up to just another game of the sort the authorities like to play. It’s similar to the suspense the legal system is endeavoring to inflict on those under suspicion for their role in the May 6 protest.

While police are keeping tabs on Navalny and Baronova — and most likely others — investigators are still deciding what charges to bring.

It had been a largely peaceful demonstration against Putin and corruption, but a street battle unfolded between police and several dozen young men and women. Navalny was detained while standing dozens of yards away, preparing to speak from a stage. Since then, his apartment and the apartments of other protest leaders have been searched, and the investigation is continuing. Long sentences could be in the offing.

On Monday, newspapers here reported that Moscow’s police leaders admitted their men had acted illegally in breaking up the demonstration, by covering their badges. They promised that officers who could be identified have been punished.