The Russian Police on Sunday arrested Opposition leader Aleksei Navalny from Moscow and scores of others who participated in countrywide protests against corruption. As many 99 similar rallies were held from Vladivostok in the far east to Kaliningrad in the west to protest against President Vladimir Putin. The agitations have been touted as the biggest in Russia in the past five years, reported The New York Times.

While the Moscow Police said around 500 had been arrested, a rights group countered the claim and said the number could be as high as 1,000. Local and foreign journalists, students and small Opposition party members were among those taken into custody.

The police said the protesters were detained because they held the demonstrations without permission. A reporter with The Guardian, Alec Luhn, was among those arrested for photographing the police action. Officers frisked him and confiscated his phone. Luhn, along with 16 others, were released after five hours, reported The Guardian.

Opposition leader Navalny was taken into custody when he tried to join protesters along Tverskaya Street in Moscow. Agitators had tried to prevent the police from arresting him. “No need to fight to get me out. Walk along Tverskaya. Our topic of the day is the fight against corruption,” he later tweeted. Navalny said the police also detained employees of his Anti-Corruption Foundation, which had organised the rallies, reported the BBC.

In addition to Putin, protesters also demanded the resignation of Prime Minister Dmitry Medvedev over corruption allegations. They shouted slogans such as “Down with Putin!”, “Russia without Putin!” and “Putin is a thief!”. Medvedev has been accused of maintaining a fortune, including mansions, yachts and vineyards, far beyond his official salary.

A Russian leader in Washington, Senator Ben Sasse, condemned the police action. “Putin’s thugocracy is on full display. The United States government cannot be silent about Russia’s crackdown on peaceful protesters,” he said. Soon after, acting spokesperson for the State Department in Washington Mark Toner said the US “strongly condemns the detention of hundreds of peaceful protesters throughout Russia on Sunday”.

The protests come at a time when Russia is gearing up for its presidential election next year. Putin is expected to contest, eyeing a fourth term.