CARACAS, Venezuela — President Nicolás Maduro began a new six-year term Thursday even as opponents — at home and abroad — sought new leverage to weaken his rule and attempt to drive him from power.

His critics have long been divided and outmaneuvered by Maduro, who has proven resilient despite Venezuela’s near-total economic collapse and deepening rifts with the United States and others.

But his inauguration for a second term appeared to stir new gambits by Maduro’s opponents.

The opposition-controlled National Assembly — stripped of its powers by Maduro in 2017 — declared the president an “usurper” and called itself the country’s only “legitimate power.” The assembly’s newly named president, Juan Guaidó, said in a video statement that the body would work with foreign powers toward a political transition in Venezuela.

Maduro wears “a paper crown,” he said.

“We will assume the responsibility as the only legitimate power representing the people,” Guaidó added.

Any attempt to pressure Maduro from power, however, carries substantial risks and significant hurdles.

Maduro, a 56-year-old former union leader, won an election last May that was considered by a host of foreign governments and opponents to be a fraudulent power grab. Amid a severe crisis marked by food and medical shortages, he has held on to power through a wave of repression and arrests that has forced many dissenting Venezuelan politicians into exile or hiding.

In recent days, Maduro has threatened to dissolve the National Assembly altogether. The opposition has been debating the possibility of declaring a transitional government, with some in favor and others opposed. If the assembly did move in that direction, experts say, it could provoke Maduro to take more aggressive steps.

Venezuela’s often disorganized opposition has yet to produce an outline or road map for pressuring Maduro to leave. With the opposition lacking any real power domestically, any decision to try to forge, say, a transitional government, would be largely dependent on the support of the international community to give it any real heft.

Opposition leaders called a meeting for Friday to discuss their next steps.

“Previous attempts to build pressure against Maduro have not borne fruit,” said Michael Shifter, president of the Inter-American Dialogue, a Washington-based think tank. 

Still, opponents are hoping that the Trump administration and others could seize on the assembly’s attempt to assert itself to possibly weaken Maduro.

Vice President Pence issued a strongly worded tweet with the Spanish hashtag Libertad, or Liberty, that called Maduro’s inauguration a “sham.”

“The US does not recognize the illegitimate result of a stolen election,” Pence tweeted. “We’ll continue to stand [with] the people of Venezuela & against Maduro’s corrupt regime until freedom & democracy prevail in Venezuela!”

Secretary of State Mike Pompeo appeared to draw on the National Assembly’s language, condemning “Maduro’s illegitimate usurpation of power” in a statement.

Pompeo’s statement also noted “support for Venezuela’s National Assembly, the only legitimate branch of government duly elected by the Venezuelan people.”

“It is time for Venezuela to begin a transitional process that can restore the constitutional, democratic order by holding free and fair elections that respect the will of the Venezuelan people,” the statement said.

On his inauguration day, Maduro’s international isolation only appeared to deepen.

The Organization of American States voted not to recognize Maduro’s new term, with 19 nations supporting the motion, six against and eight abstaining. Peru and Paraguay recalled their diplomats from Venezuela. Officials from the European Union issued stark condemnations.

“Maduro’s mandate is illegitimate,” tweeted Antonio Tajani, president of the European Parliament. “We will continue fighting for the liberation of political prisoners and democracy in Venezuela.”

Chrystia Freeland, Canada’s foreign minister, said in a statement that her nation “rejects the legitimacy of the new presidential term of Nicolás Maduro. We call on him to immediately cede power to the democratically-elected National Assembly until new elections are held, which must include the participation of all political actors and follow the release of all political prisoners in Venezuela.”

Maduro was sworn in at the Supreme Court in the center of Caracas. An orchestra played traditional Venezuelan songs as he walked on a red carpet, holding hands with his wife, Cilia Flores. Hundreds of people watching on the building’s upper floors cheered and waved flags.

Outside the building, a crowd of thousands dressed in red shirts were dancing to pro-government campaign songs.

“I came today because we support our president and wanted to see him get sworn in. It was like a party. It was great,” said Rudy Hernández, a 46-year-old employee at the mayor’s office in the Sucre municipality in Caracas. “The international community tries to intervene to not let the government do its work, and that’s why life has gotten hard here.”

In his speech, Maduro blamed the United States for Venezuela’s woes, but he also offered a mea culpa of sorts.

“I want a new beginning,” he said. He added, “I want to fix the mistakes, the many mistakes that have been made.”

Faiola reported from Miami.