Clashes with police continued in parts of the Venezuelan capital of Caracas Saturday on the eve of a controversial election that has deepened the political crisis gripping the South American nation.

In opposition strongholds in the relatively wealthy eastern part of the capital city, teenagers manned barricades of tree branches, garbage and barbed wire torn from nearby buildings, the Associated Press reports. Clashes with police began late Friday afternoon and lasted into the night.

Other parts of the city were calm, however, as the socialist government of President Nicolás Maduro prepared for Sunday’s vote to elect members of a special assembly that would rewrite the country’s 1999 constitution created under President Hugo Chávez.

Opposition leaders have called for massive marches on the day of the vote, arguing that the election has been structured to ensure that Maduro’s ruling socialist party dominates.

The opposition says the government is so afraid of low turnout that it’s threatening to fire state workers who don’t vote and take away social benefits like subsidized food from recipients who stay away from the polls.

The resulting National Constituent Assembly could become one of the most powerful organs in the country, creating…