Russian police arrested about two dozen protesters Sunday in Moscow, a week after more than 1,000 others were detained during a large-scale rally organized by a leading critic of President Vladimir Putin.

The Russian state news agency Tass reports that Sunday’s arrests were made while protesters tried to conduct unauthorized marches toward the Kremlin from two public squares in Moscow.

Police had blocked off Pushkin Square, a traditional gathering place for demonstrators. Authorities also blocked access to several Internet websites the government said promoted “a planned illegal anti-government protest” in or near Moscow’s Red Square.

The protests were organized by prominent Kremlin critic Alexei Navalny. He and hundreds of others anti-corruption demonstrators demanding the resignation of Prime Minister Dmitry Medvedev were detained last week.

Some critics of the Kremlin portray Putin as an overseer of a corrupt government that has awarded select friends and associates with vast sums of wealth.

The protests are occurring a year before a Russian presidential election in which Putin is expected to seek a fourth term. Navalny would like to run against the heavily-favored Putin, despite a questionable conviction on fraud charges that would technically disqualify him.

Last week’s protests were the largest opposition rallies Russia has seen in several years.