Vladimir Putin completed the job swap Tuesday that so enraged voters when he announced it last fall: A day after Putin was inaugurated as president, Dmitry Medvedev succeeded Putin as prime minister.

Though protesters still roamed the streets Tuesday, trying to avoid police and periodic downpours, Putin and his people showed little inclination to engage them with anything but contempt.

In the afternoon, a legislator asked Dmitry Peskov, Putin’s press secretary, whether he regretted saying riot police who clubbed protesters at a legal demonstration Sunday should have treated them even more harshly.

“They were too soft,” Peskov said, according to a tweet from Duma deputy Ilya Ponomarev. “Protesters who hurt riot police should have their livers smeared on the asphalt.” There was no immediate response from Peskov to the reported comment, which caused an outcry among opposition activists.

Police on Tuesday afternoon said they had detained more than 300 people in the previous 24 hours. They kept snatching protesters off the street, apparently trying to keep them off-balance, and often the only apparent offense was wearing a white ribbon symbolizing protest. As Michael Idov of Russian GQ tweeted: “Nothing like seeing people arrested for an accessory.”

Police acted with relative restraint Tuesday, perhaps hoping that rain and lack of sleep would drive away demonstrators more effectively than nightsticks. Some protesters joked that the authorities must have seeded the clouds to demoralize them. The authorities’ moderation was unlikely to last until Wednesday, when Russian armed forces march through Red Square in a show of force to commemorate victory in World War II, known here as the Great Patriotic War.

As night fell, the riot police got their orders and moved forcefully on the protesters, driving them from a park, where they had been singing and talking, along a boulevard to Pushkin Square and to the Itar-Tass news agency building, where police began making numerous arrests among the crowd of several hundred.

Alexei Navalny, a charismatic anti-corruption blogger, was pushed into a police van along with Ksenia Sobchak, who is known as the Paris Hilton of Russia and is the daughter of Putin’s St. Petersburg mentor. She is a television broadcaster with journalistic credentials.

Very quickly, one observer said, much of the Moscow Twitter universe was bound for the police station. That didn’t stop the iPhone-equipped generation, and they were soon demanding by Twitter that authorities equip patrol wagons with WiFi if they intended to arrest the entire creative class.

Apparently unwilling to brook dissent from any quarter, Putin treated the Duma deputies dismissively in his first appearance before them since his inauguration, although the majority approved his choice of former president Medvedev as prime minister in a 299 to 144 vote.

His discussion of economic problems — which he blamed on the Soviet past — set off a murmur among Communist deputies, which Putin promptly silenced with trademark insensitivity.

“Yes, my friends, let’s not debate that. The point is that nobody wanted what we were producing — don’t wave your hands. Because nobody was buying our galoshes except for Africans, who had hot sand to walk on.”