Thousands of Venezuelans have marched in protest against the banning from politics of opposition leader Henrique Capriles for 15 years.
In Caracas, police used tear gas to prevent demonstrators reaching the offices of the national ombudsman.
Saturday’s protest came after a week of anti-government demonstrations.
They were initially sparked by a Supreme Court ruling to curb the powers of the national assembly, a move which was later overturned.
Security police fired tear gas on one major avenue in Caracas while in the city of San Cristobal they shot rubber bullets towards protestors.
Many people carried signs reading “No to dictatorship!” and “Capriles for President”.
In the Caracas protest there was a moment of silence in memory of a young man shot dead on Thursday by police during demonstrations.
Mr Capriles has been at the forefront of demands for a recall referendum on President Nicolas Maduro.
A former presidential candidate who has run twice, he is seen as the oppositions’s best hope of defeating Mr Maduro in elections scheduled for next year.
The ruling by the Venezuelan comptroller said the ban on Mr Capriles was due to “administrative irregularities” in his role as governor.
Henrique Capriles is the latest in a series of prominent opposition politicians to be put out of action.
Two years ago, Maria Corina Machado, a former congresswoman was banned from office as was a former mayor, Daniel Ceballos.
In 2015 another prominent opposition leader, Leopoldo Lopez, was sentenced to nearly 14 years in prison on charges of inciting violence during anti-government protests in 2014.
Venezuelans are dealing with the effects of a harsh economic crisis that has millions skipping meals, unable to afford soaring prices for basic goods and facing long lines for scarce products.
Mr Maduro’s socialist government have said that a US-backed business elite is responsible for Venezuela’s economic downturn and that it is trying to organise a coup to impose right-wing rule.