Protesters have stormed and set fire to Paraguay's Congress after the Senate secretly voted for a constitutional amendment that would allow President Horacio Cartes to run for re-election, a change that will also require approval by the House.
The country's constitution has prohibited re-election since it was passed in 1992 after a brutal dictatorship fell in 1989. "A coup has been carried out. We will resist and we invite the people to resist with us," said Senator Desiree Masi from the opposition Progressive Democratic Party.
Television images showed protesters breaking windows of the South American country's Congress after several hours of escalating violence and confrontations with police.
Demonstrators burned tyres and removed parts of the fences surrounding the Congress building, and police in riot gear responded by lobbing tear gas and firing rubber bullets.
Several politicians and journalists were injured, local media reported, and Interior Minister Tadeo Rojas said many police were hurt.
The number of casualties was unknown. Several people were inside Congress as the flames spread. Television images showed firefighters arriving on foot to fight the blaze.
The Senate voted earlier on Friday during a special session in a closed office in Congress rather than on the Senate floor. Twenty-five MPs voted for the measure, two more than the 23 required for passage in the 45-member upper chamber.
Opponents of the measure, who claim it would weaken Paraguay's democratic institutions, said the vote was illegal.
The proposal goes to the House, where it appeared to have strong support. A vote expected to take place early on Saturday was called off until the situation calmed down, said the chamber's President Hugo Velazquez.
Several Latin American countries, including Paraguay, Peru and Chile, prevent presidents from running for consecutive terms in a region where the memories of military dictatorships remain ripe.