MOSCOW — Thousands of opponents of President Vladimir Putin recently crowded into a Moscow square infamous as the location of the state security forces, vowing not to let up pressure on their government after a year of protests that started with grand hopes for change in their country and ended far more tentatively.
They braved near-zero temperatures and official warnings against the gathering to hold an illegal protest in front of the imposing security headquarters. Many of the roughly 3,000 protesters laid flowers near a stone that commemorates victims of Soviet gulags in honor of what they say are modern-day political prisoners.
But the protest earlier this month was far smaller than earlier marches that had tens of thousands turning out onto the streets of Moscow, and its top leaders were arrested long before they had any chance to energize the crowd.
The opposition movement has faced deep difficulties in sustaining its energy since Putin prevailed in March elections and took quick action to crack down on dissent in the country.
For protesters such as Ekaterina Korobtsova, the last year has been radicalizing but also edged with disappointment.
‘‘I expected there’d be more people,’’ she said as she walked into the square, bundled under heavy layers to defend against biting winds, past rows and rows of heavily armored police officers that she derided as cosmonauts, for their spaceman-like helmets.
Before what many charged were fraudulent parliamentary elections in December of last year, Korobtsova, 45, did not go to protests, she said. But like many others of her prosperous generation, she grew fed up with the corruption that touches so many aspects of life in her country of 143 million.
So Korobtsova, a freelance translator and former investment adviser, started heading out into the streets to fight Putin’s 12-year rule, along with tens of thousands of her peers.
The first time — at Bolotnaya Square, where high turnout shocked organizers and the government alike — was unsettling, she said, because she did not know what to expect. But soon protest became normal, even fun. The mother of a 9-year-old boy, she was able to recite the proper procedure for helping a person escape from riot police as though she had known it since childhood.
Even ‘‘if they start using tanks, I think people will still come,’’ she said at a fashionable coffee shop owned by a socialite who is one of the opposition movement’s unlikely leaders. ‘‘They can’t scare us,’’ Korobtsova said.
In the first heady months, the sense of mass mobilization gave the opposition movement an unusual potency as the white ribbons that are their symbol were displayed on lapels in Moscow and St. Petersburg.
But they were never able to offer a convincing alternative to Putin, and no one disputes that he was the clear winner of a March election that officially gave him 64 percent of the vote. Now, with Putin settling in to another six-year term, with harsh new laws passed against protest, and with criminal charges filed against many opposition leaders, the future appears far less hopeful.
‘‘A whole year of our lives has gone by, and what has changed?’’ Korobtsova said. These days she dutifully turns out to protests to remind Putin that not everyone accepts him, even as she fantasizes about moving the United States, where she studied for two years in the 1990s.
‘‘Most people with money are trying to escape,’’ she said.
In the recent demonstration, protesters came in defiance of Moscow authorities who denied permission to gather at Lubyanka Square in front of headquarters of what was once the KGB, of which Putin was once an officer. They came despite risks that have increased significantly since they began the wave of protests a year ago.
Shortly after Putin was inaugurated in May, he instituted laws that pushed fines for illegal protest to about $9,000 for individuals, up from $60, and as much as $48,000 for organizers, up from $1,160. The average yearly salary in Russia is about $20,700.
‘‘What authorities are doing with the protest movement, they are making it more radical,’’ said Lilia Shevtsova, a political analyst at the Carnegie Moscow Center. ‘‘With the first wave subsiding, we have a paradox. The open movement is dwindling, but a general mood of fury within the protests is growing.’’
Authorities have pursued criminal charges against top opposition leaders, the newest of which were filed against Alexei Navalny, a lawyer and blogger who has been able to bridge division between right-wing nationalists and die-hard leftists. He was accused of embezzlement.
He spoke very briefly to protesters before he was bundled into a police van and detained until after the demonstration was dispersed. Three other organizers — Ksenia Sobchak, Ilya Yashin, and Sergei Udaltsov — were also detained, with police saying they had called on people to participate in an unsanctioned event.
Putin has derided the protesters, but he has also made moves to coopt their main issues, including firing his defense minister amid accusations of corruption.