By Andrei Makhovsky and Oleg Shchedrov
MINSK (Reuters) - Belarussian riot police broke up a protest march on Saturday just hours after a rally at which a top opposition leader proclaimed the launch of a movement to "liberate" the country from President Alexander Lukashenko.
With the march dispersed just outside the city center, police began hunting down opposition leaders.
Opposition leader Alexander Milinkevich, in a public challenge to Lukashenko, told the rally that more and more people were losing their fear of the man who has run Belarus with a rod of iron for 12 years.
"I declare the creation of a Popular Movement for the Liberation of Belarus," said Milinkevich, one of two opposition candidates defeated by Lukashenko in a March 19 election that activists say was blatantly rigged.
But after the rally broke up several hundred protesters headed for a pre-trial detention center at the urging of a second opposition leader, Alexander Kozulin.
It was to that center that police took 300 demonstrators rounded up early on Friday morning, according to opposition figures.
Police in full riot gear, began beating their shields with truncheons, stopped the march, fired stun grenades and charged protesters. At least two people were injured and taken to hospital.
Opposition protesters said they saw riot police haul Kozulin from a car and detain him. Milinkevich was not immediately picked up, though his spokesman was detained.
In an initial comment, Milinkevich accused Kozulin, his fellow opposition candidate, of foolhardiness in leading protesters away in a march after the successful rally.
Asked whether he now expected blanket arrests, he said: "I do not want to be a prophet, but one may expect the worst".
"STORMING THE REGIME"
Addressing the rally, Milinkevich, 58, a soft-spoken former lecturer, said the wave of protests against Lukashenko since the election represented "only a first storming of the regime.
"We will keep on working, but we will not put off the next storming for another five years. We will fight above all else for fair and honest elections," he declared.
Lukashenko has made no major public statements since describing his victory as the failure of a Western-backed revolution he said was being fomented. He is due to be inaugurated on March 31.
Demonstrators are demanding a re-run of the poll, which returned to power for five years a president accused in the West of pursuing Soviet-style policies, closing down media and cracking down on rivals.
Events in Belarus have set Russia, which endorses his victory, at odds with the United States and western Europe.
The mood was buoyant and festive among protesters trooping to Yanka Kupala park for an unauthorized rally after riot police stopped them from massing on October Square, the site of a tent camp cleared by police on Friday.
Chanting "Shame!" and "Long Live Belarus!", the crowds gathered round the podium and listened to speaker after speaker.
In line with the pattern this week, police initially showed tolerance unusual for the tightly controlled ex-Soviet state and refrained from using force. Dissent is normally quickly snuffed out by the state security service.
Some observers have speculated that Lukashenko may be under pressure from Russia, his most powerful backer, not to allow violent action by the police that could embarrass Moscow in the year when it chairs the G8 group of rich nations.
Milinkevich, credited with only 6 percent of the vote to Lukashenko's 83 in the election, had urged supporters to mass "no matter what" in October Square.
The rally was also billed as a commemoration of the independence day of a short-lived Belarussian republic in 1918.
"It's a great holiday, even more -- it is a beginning of our victory. People are sick and tired of Lukashenko," said Leonid Avtukhov, 38, a communal worker who came to the rally wrapped in the nationalist red-white flag banned by Lukashenko.