Police detain Pussy Riot member Maria Alyokhina in central Moscow on Feb. 24 during a protest against the sentencing of seven people accused of instigating riots on the eve of Vladimir Putin's inauguration as president in 2012. (AFP/Getty Images)

Seven people who demonstrated against Vladimir Putin on the eve of his presidential inauguration in May 2012 were sentenced to as much as four years in prison Monday, while an eighth was given a suspended sentence.

They were ordinary people, not leaders, and their arrests were widely considered a warning to other demonstrators to stay at home or risk severe punishment. That message was elaborated on later Monday. First, more than 200 people protesting the sentences outside the court building were detained. Then, when Russian opposition leaders called for a protest Monday evening, 420 people out of the about 500 who showed up were detained, according to police.

Andrei Mironov, a longtime activist, headed to Manezh Square near the Kremlin on Monday evening to see what was happening. He and others have been fearing an even tougher crackdown on dissent after the Olympics.

Mironov was on the corner near Hotel National, not far from Red Square, when he called a journalist to say that people were gathering. As he spoke to her loudly in English, riot police threw him into a police van.

There he found himself in the company of Maria Alyokhina and Nadezhda Tolokonnikova, members of the punk rock group Pussy Riot. He handed the phone to Tolokonnikova, who said the two women had been detained earlier in the day at the court but had been released. Now the authorities were threatening them with charges of disobeying police, she said.

“They’re afraid,” she said of the authorities. “They’re afraid of what’s happening in Ukraine.”

Mironov agreed. He said the police presence had been unusually heavy, both at the court earlier in the day and at the square in the evening. “They’re worried the revolution in Ukraine will set off the same thing here,” he said. And, in the morning, demonstrators had been shouting “Maidan,” referring to Ukraine’s Independence Square, the center of that country’s protest movement.

Then, still in the police van, he handed the phone to a 24-year-old German tourist from Cologne. She spoke on the condition of anonymity, fearing police reprisals if they knew she had spoken to a reporter. She and a friend were standing on the corner, she said, heading toward Red Square. Suddenly, she said, five police officers grabbed her and hauled her away. They did not take her friend.

About the same time, opposition leader Boris Nemtsov was being detained at a square across from the Bolshoi Theater, according to the Interfax news agency. Alexei Navalny, another leader, was detained — for the second time Monday — and taken away in a police van.

Back in the first van, Mironov handed the phone to Vladimir Akimenkov, among those who had been arrested and charged over protests in Moscow’s Bolotnaya Square in May 2012. He had suffered months in jail, his eyesight deteriorating dangerously, until he was freed under an amnesty in December.

“We did nothing,” he said. “We are peaceful citizens.”