Thousands of Czechs gathered in central Prague on Monday to celebrate the 25th anniversary of the launch of the Velvet Revolution that toppled communism -- but festivities turned into an appeal for President Milos Zeman to resign.

The center of the rally was a street in downtown Prague where police cracked down on a peaceful anti-communist student march that came a week after the collapse of the Berlin Wall on Nov. 17, 1989.

The demonstrations began with fiery speeches against the hard-line communist regime at a university campus, prompting thousands of students to march downtown. The police blocked the street from both sides, squeezing the protesters with armed vehicles before attacking them with truncheons; hundreds were injured. Undeterred, the students went on strike and crowds mushroomed in the days that followed.

On Dec. 29, 1989, dissident playwright Vaclav Havel became Czechoslovakia's first democratically elected president in a half-century.

Under his leadership, the country became a champion of human rights -- and many Czechs believe Zeman has betrayed that legacy. They cite his pro-Russian stance in the Ukraine conflict, recent praise of visiting Chinese leaders and comments seen as downplaying police brutality 25 years ago.

He also used a strikingly vulgar term in explaining in a live radio broadcast why he did not consider the Russian punk group Pussy Riot -- who spent time in a Russian prison camp over hooliganism charges -- political prisoners.