The government of Venezuela's President Nicolás Maduro launched a takeover of the country's legislature Sunday by blocking opposition from entering the National Assembly to vote for head of the chamber.

Maduro's government de facto installed its own candidate as head of the National Assembly, preventing Juan Guaidó, who is recognized by almost 60 countries as the true president of Venezuela, from retaining the position. Guaidó, who has attempted to unseat Maduro, lost his seat to Luis Parra who announced his candidacy Sunday morning, The Washington Post reported.

Opposition officials called the move a "parliamentary coup" by Maduro's government to secure more of a dictatorship by taking over what was considered one of the last democratic institutions of Venezuela.

"Parliamentary coup by the Maduro dictatorship against the National Assembly. Without a vote or quorum, ruling-party lawmakers and corrupt lawmakers swear in a false leader," Guaidó's communications team posted on Twitter, according to the Post.

Security forces with allegiance to Maduro guarded the assembly building, preventing opposition lawmakers from entering but allowing lawmakers who support Maduro to head in, including some allegedly involved in a scheme to buy votes, the Post reported.

Guaidó, who was expecting reelection today, tried to climb a wrought-iron fence to get in, according to videos on Twitter documenting the incident.

Parra was sworn in, with the support of 40 lawmakers in Maduro's party, but the opposition argues the lawmakers did not meet the minimum number required in the chamber for a vote.

"Today we want to open the doors to the future of this parliament," Parra said during his swearing-in speech, according to the Post. "To the people that today expected a different message, we will continue to seek reconciliation."

The opposition plans to hold its own vote for the head of the National Assembly Sunday in response to the earlier events, the newspaper reported.

The U.S. has supported Guaidó as the true president and will likely continue to, but the loss of his government title could affect if other countries are able to label his as the true president.

"What the regime is doing now at the National Assembly goes completely against the will of the people and the laws that govern the process," the U.S. mission to Venezuela said in a tweet, according to the Post. "Democracy can't be intimidated."