By C.J. Chivers The New York Times
MINSK, Belarus The riot police dispersed a fresh challenge to President Alexander Lukashenko, blocking thousands of anti-government demonstrators from reaching the central square in the capital and later arresting a top opposition leader.
The opposition leader, Alexander Kazulin, was seized Saturday as he was leading a march on a prison where opposition members were being held. Policemen shoved and beat many of the protesters on the streets and arrested at least one other opposition organizer.
Before the police seized Kazulin, who had challenged Lukashenko in the March 19 election, the two sides had been jostling throughout the day to show their strength, and the first hour brought a surprising show of opposition resolve.
In spite of arrests throughout the week and a police crackdown that seized many of the most active members of the opposition, at least 6,000 people appeared at noon Saturday in central Minsk, where they were met by phalanxes of riot policemen with clubs. Some demonstrators carried flowers. They chanted: "Truth! Truth! Truth!" and "Freedom! Freedom!"
After being blocked from October Square during a tense hour of confrontations with formations of riot policemen, the crowd dispersed and reassembled at nearby Yanka Kupala Park, where another opposition leader said they would not halt their campaign of civil disobedience.
"What is going on in Belarus can be compared to the storming of a fortress," said Alexander Milinkevich, the principal challenger to Lukashenko in the disputed presidential election. "This was the first storming. We will use peaceful methods. We will surround that fortress and we will not retreat."
Later, the demonstrators marched on the prison and were dispersed by the police with stun grenades, participants said. Kazulin was arrested by a team of special forces officers who rushed him and snatched him from the crowd, witnesses said. The police also separately arrested Milinkevich's spokesman.
The unauthorized rallies continued a week of small but intensive public defiance against Lukashenko, who is often called Europe's last dictator and whose police state, an island of Soviet nostalgia and communist ideology, is feared for its brutality.
Lukashenko was re-elected to a third term March 19 in a vote that the West and the opposition regard as rigged.
The United States has called for a new election and said it would impose penalties against Lukashenko and his top officials.
Leaders of the European Union, meeting in Brussels on Friday, declared the election "fundamentally flawed" and also said they would impose new sanctions against Belarus.
Milinkevich has called for another demonstration Saturday, an unofficial holiday celebrating a brief period of Belarussian independence in 1918.