BELGRADE, Serbia (AP) — Hundreds of protesters opposed to lithium mining in Serbia blocked roads near a government building where the Balkan country's populist president was awarding state decorations Tuesday, which was a national holiday.

Police cordons prevented the demonstrators from getting too close to the venue in New Belgrade as President Aleksandar Vucic welcomed guests inside. Among those honored by Vucic on Serbia's Statehood Day was actor Johnny Depp.

Several protest-related incidents were reported, including angry drivers pushing through crowds stopping traffic.

A group of environmental activists have camped outside the presidency building in central Belgrade for several days while demanding a legal ban on lithium and borate mining in Serbia. The activists called Tuesday's rally in another part of the capital to draw further attention to their cause.

Environmental protests have become a challenge for Vucic's government ahead of Serbia's April 3 general election. The government tried to defuse the movement by saying it had cancelled a planned lithium mining project in western Serbia by the Rio Tinto company.

The activists now are demanding the banning of lithium and borate mining in the entire country. They have argued that cancelling the Rio Tinto project was temporary and did not guarantee there wouldn't be similar projects in the future.

Savo Manojlovic, from the Kreni-Promeni, or Go-Change group, said the protests would continue in advance of the election. Serbia must tackle a number of environmental problems, including poor waste management and air and water pollution, to advance toward joining the European Union.

Vucic is expected to sign a decree later Tuesday dissolving parliament so a snap parliamentary election could be held at the same time as the presidential elections and municipal ballots in Belgrade and several towns.

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