Russian riot police beat protesters with batons and hauled away dozens on Sunday after skirmishes broke out at a demonstration in Moscow against Vladimir Putin on the eve of his return to the presidency.
Opposition leaders Alexei Navalny, Boris Nemtsov and Sergei Udaltsov were among those detained at the rally, at which police tried to push back protesters who advanced towards them holding metal crowd barriers, Reuters reporters at the rally said.
Police, forming a line to prevent protesters moving towards a bridge leading across the Moscow river to the Kremlin, struck several protesters on the head and the demonstrators then fought back with flagposts before the scuffles died down.
The violence came at the end of a day of protests in several cities against Putin, who will be sworn in for a third term as president on Monday at a ceremony inside the Kremlin at which the head of the Russian Orthodox Church will bless him.
Many of the protesters are angry that Putin is extending his 12-year domination of Russia, despite being undermined by large protests from December to March, and fear he will stifle political and economic reform in his six-year term.
"History shows that if one person rules for a long time, especially using the methods of a dictator, nothing good comes of it for the country," said an 85-year-old World War Two veteran in Moscow who gave his name only as Alexander.
Many are frustrated that the same faces are still leading Russia. After Putin ushered his ally Dmitry Medvedev into the Kremlin and became premier in 2008 because of constitutional term limits, the two have agreed simply to swap jobs.
Holding a banner saying "Putin lost my trust", 44-year-old Moscow protester Andrey Asianov said: "I trusted Putin as long as he ruled within the bounds of the constitution but our law limits the presidency to two consecutive terms. He and his clown Medvedev spat on that."
At least 20,000 people protested in Moscow under banners and flags, chanting "Russia without Putin" and "Putin - thief". Police said four officers were hurt and Udaltsov, Nemtsov and Navalny had been detained for "incitement to mass disorder".
Udaltsov, a leftist leader, was taken away as he tried to address the crowd from a stage and Navalny, an anti-corruption blogger, was dragged off after trying to organise a sit-in protest calling for Putin's inauguration to be scrapped.
In other protests, demonstrators carried a black coffin bearing the word "democracy" through the Pacific port city of Vladivostok. Several people were detained there and at protests in the Urals city of Kurgan and Kemerovo in western Siberia.
The Moscow protest was marred by the death of a photographer who Itar-Tass news said fell from a balcony as he tried to take pictures of the rally.
The clashes were the worst since police moved in to disperse hundreds protesters at or after rallies the day after Putin's March 4 election victory, which the opposition said was achieved with the aid of electoral fraud.
But the sting has gone out of protests since Putin won the election with almost 64 percent of the vote.
The former KGB spy, simply ignored the protests. He looked relaxed as he attended a religious ceremony led by Russian Orthodox Patriarch Kirill that marked the transfer of a revered icon from a museum into the hands of the Church.
Thousands of Putin supporters attended a separate rally in Moscow that was intended to show he enjoys more support than the opposition.
Putin, 59, has dismissed allegations that widespread fraud helped him win the presidential election and secured victory for his United Russia party in a parliamentary poll in December, but the opposition says he was illegitimately elected.
Medvedev has pushed only limited political reforms through parliament following the protests, which at their height attracted tens of thousands of people in Moscow and St Petersburg but did not spread outside big cities.
The demonstrations have deprived Putin of his aura of invincibility, and opposition candidates have been trying to get a foothold on power in municipal elections, but the size of the protests on Sunday was unlikely to trouble the president-elect.
Even so, protesters said Sunday's rallies were another signal to Putin that Russia had changed as he returns to the Kremlin after four years absence, even if change was coming slowly two decades after the collapse of the Soviet Union.
Such protests were unthinkable until December, when anger over the electoral fraud allegations spilled over.
"Civil society is taking shaping little by little. People will concentrate more on local problems and change things from the bottom up. It's clear we aren't going to march on the Kremlin," said Maria Golinchuk, 25, a kindergarden teacher.