Protestors set fire to Paraguay's parliament building and rioted throughout the capital, Asuncion, following a Friday night Senate vote to remove current presidential term limits.
At least one opposition activist was killed and dozens arrested in the aftermath.
Reuters reports that firefighters were quick to extinguish the flames, but rioters clashed with police elsewhere in Asuncion, who used rubber bullets and water cannons to control crowds.
On Saturday, Paraguayan authorities announced that opposition activist Rodrigo Quintana had died during the riots.
The protests were spurred by a constitutional amendment to do away with a one-term restriction on the presidency. That rule was enshrined in the country's constitution following a 35-year dictatorship that left many Paraguayans opposed to assigning a long tenure to any one ruler.
The new amendment would allow President Horacio Cartes — and former presidents — to run for a second term and was passed by a majority of the Senate. As the Associated Press notes, the party of Cartes leads in the legislature:
"The process to pass the amendment began on Tuesday when 25 senators changed the internal procedures to speed up the vote against the wishes of Senate President Roberto Acevedo and other members of the chamber. ...
"The measure for a constitutional amendment allowing for presidential re-election was backed by 25 of the country's 45 senators. The yes votes came from members of the governing Colorado Party and from several opposition groups.
"After approval in the Senate, the proposal went to the Chamber of Deputies, where 44 of the 80 members belong to the Colorado Party. Approval there would require the scheduling of a national referendum on the amendment."
Opposition politicians were quick to call the Senate vote illegal, citing that not all members were present.
"My colleagues have carried out a coup because of the irregular and illegal manner in which they modified no less than the Constitution," Sen. Luis Alberto Wagner of the opposition Authentic Radical Liberal Party was quoted as saying by the news service.
That limit on presidential terms was added to the country's modern constitution in 1992, after 35 years under military dictator General Alfredo Stroessner, who took power in a coup.