Many Czechs have used the anniversary of their country's 1989 anti-communist Velvet Revolution to voice their opposition or support for President Milos Zeman.

Both camps organized gatherings and marches in Prague to commemorate Thursday's anniversary. Participants traded insults, but anti-conflict officers intervened before fights could break out.

In one incident, riot police had to separate far-right marchers from activists on the left who tried to block them.

Zeman, who is known for his strong anti-migrant rhetoric, divides the nation with his pro-Russia stance and support for closer ties with China.

Meanwhile, thousands came downtown to light a candle at a monument to the November 17 student demonstration that triggered the 1989 revolution.

Zeman, who welcomed Donald Trump's victory in the U.S. presidential election, remained at the presidential palace outside Prague.