After hours of increasingly violent protest both ahead of and following a vote on a controversial change to the country's presidential election process, angry demonstrators broke into and set a fire on the ground floor of Paraguay's Congress building in its capital, Asuncion.

Protesters clashed with police for several hours in the capital city following a secret vote by 25 senators for a bill that would allow President Horacio Cartes to run for reelection. Demonstrators contend that this is unconstitutional.

Instead of being held on the Senate floor as usual, the vote took place in a closed office in Congress.

Police have used rubber bullets and water cannons to disperse the crowd, but protesters continue to surround the building and, according to reports, have broken in and are vandalizing the interior. Several journalists and politicians have been injured according to local media reports.

— Chismosas Paraguay (@ChismosasParag2) March 31, 2017

— Laurence Blair (@LABlair1492) March 31, 2017

Senator Desiree Masi from the opposition Progressive Democratic Party said, "A coup has been carried out. We will resist and we invite the people to resist with us."

— Kurt Wieser (@kwieser76) April 1, 2017

Tadeo Rojas, interior minister, said that a small group of protesters injured police as well, telling a press conference, "The national police were not under any instruction to repress. They were attacked."

The controversial bill will now go to Paraguay's House, where it was expected to be voted on Saturday morning.

If passed, the change would apply to Cartes, as well as future presidents. Paraguay's presidents are elected to five-year terms.