Updated

Russian police broke up anti-Kremlin protests in Moscow and St. Petersburg on Sunday, and detained more than 100 demonstrators, including several opposition leaders.

In Moscow, several hundred demonstrators gathered in a central square, defying a ban imposed by authorities. The protesters said their rally was banned in violation of the Russian constitution's guarantee of the right to gather.

They denounced the policies of President Dmitry Medvedev and his predecessor and mentor Vladimir Putin, who continues to wield broad powers as Russia's powerful prime minister.

Protesters shouted "Shame!" and "Down with Putin!" as Moscow police in riot gear pushed them into buses. Several dozen protesters were detained, including opposition leaders Boris Nemtsov, Eduard Limonov, Ilya Yashin, and the head of the Memorial rights group, Oleg Orlov.

Police spokesman Viktor Biryukov said about 300 people took part in the Moscow rally and about 100 were detained.

Police quickly dispersed a similar rally in St. Petersburg, detaining most of several dozen protesters who gathered on a downtown Nevsky Prospect. Some of the demonstrators were beaten with truncheons.

Protests also were held Sunday in Yekaterinburg, Russia's third-largest city, in the Ural Mountains; in Krasnoyarsk in central Siberia; and in the far eastern port of Vladivostok. Police didn't move to break them up, according to Ekho Moskvy radio.

Similar opposition demonstrations were held in Moscow on the last days of July, August and October. The timing is a nod to the 31st Article of the Russian constitution, which guarantees the right of assembly.

Each time, the city authorities banned the rallies, saying that some other events would be held in the area on that day.

Sunday's protest in Moscow attracted more participants than previous rallies. Opposition leaders said they hope an even larger number will attend a protest on the last day of March.

Russian authorities have shown little tolerance of dissent, banning most opposition rallies and sending riot police to detain protesters.