Bolivia’s former president Evo Morales rejected the self-proclaimed presidency of an opposition senator Wednesday, but police barred his lawmakers from entering the legislature to undo it, deepening the political crisis in South America’s poorest country.

Supporters of Morales returned to the streets and clashed with security forces; police responded with tear gas.

Bolivia has been without consensus on a leader since the resignations Sunday of Morales, his vice president and the heads of the Senate and Chamber of Deputies, all socialist members of Morales’s MAS party.

Jeanine Añez, the second vice president of the Bolivian Senate and a Morales critic, attempted to convene the upper house Tuesday to name an interim president and discuss a path toward new elections. Other opposition leaders urged support for Añez.

But MAS lawmakers, who still hold majorities in the legislature, boycotted the session. In the absence of a quorum, Añez declared herself president of the Senate, which effectively made her interim president of the country.

Bolivian media outlets called the event “surprising” and “unexpected.” But Bolivia’s constitutional tribunal quickly released a statement saying it was constitutional, the heads of the military and national police declared their support, and a senior U.S. State Department official recognized Añez as “Interim Constitutional President.”

Morales, speaking from Mexico on Wednesday, said Añez’s swearing-in had “confirmed the coup.” He said he would be willing to return to Bolivia to restore peace.

“The only way to solve this is a national dialogue,” he told reporters. “I ask the Bolivian people to end confrontations.”

Añez began work Wednesday at the presidential palace, meeting with military and police commanders. She insisted that her mandate was “strictly temporary” and that her only objective was to call elections as soon as possible. Under the Bolivian constitution, new elections must be held within 90 days of Morales’s resignation.

Opposition leaders lifted the general strike that had paralyzed the country’s largest cities for more than 20 days. Businesses began to reopen, and transportation services resumed. Most schools remained closed.

MAS lawmakers, who hold majorities in the Senate and Chamber of Deputies, tried to meet Wednesday afternoon to “nullify” Añez’s “self-proclamation,” Deputy Ruben Chambi said. But police blocked them from entering the legislative complex in La Paz.

“We are parliamentarians. We need to get to our office. We have meetings,” said Adriana Salvatierra, who resigned as Senate president Sunday but said she remains a senator. “We need to recover normality.”

Omar Aguilar, another MAS lawmaker, told reporters that “it all points to the desire to close down the legislative assembly” and challenged Añez to admit it publicly.

Morales claimed a first-round victory in the Bolivian elections last month after early returns suggested the race would go to a second round. As opposition supporters protested, he invited the Organization of American States, a U.N.-like body for the Western Hemisphere, to audit the results.

In a preliminary report released early Sunday, the OAS said it had found “manipulation” in the vote count. Morales agreed to dismiss election officials and hold new elections, but protests grew, military and police commanders withdrew their support, and by midafternoon he had resigned. He fled Monday for asylum in Mexico.

Opposition supporters celebrated Añez’s move late Tuesday with fireworks and chants.

“I congratulate the new Constitutional President of Bolivia,” tweeted former president Carlos Mesa, who finished second to Morales in the disputed Oct. 20 vote. “All success in the challenge you face. Long live the country!”

“It was all worth it,” added opposition leader Luis Fernando Camacho.

Michael G. Kozak, the acting assistant secretary of state for Western Hemisphere affairs who also recognized Añez as interim leader, tweeted, “We look forward to working with [Añez] & Bolivia’s other civilian authorities as they arrange free & fair elections as soon as possible, in accordance w/ Bolivia’s constitution.”

Añez, 52, a lawyer from the northeastern department of Beni, started her political career in 2006 as a member of a constituent assembly established to rewrite the constitution. She was elected to the Senate in 2010 and reelected in 2014.

Morales supporters protested her declaration.

“We strongly reject the self-proclamation of Señora Añez,” Andrónico Rodríguez, vice president of a coca growers federation, told reporters. “It’s completely unconstitutional.”

The State Department raised its travel advisory for Bolivia to Level 4: Do Not Travel, and ordered the departure of non-emergency U.S. government employees and family members from Bolivia “due to ongoing political instability.”

Jorge Dulon, a political scientist based in La Paz, said the path to new elections will be challenging.

“I’m worried that if the opposition fails to establish a dialogue with pro-Morales politicians, the uncertainty might be prolonged, and we won’t have elections in the stipulated timing,” he said. “I’m also worried that social movements could generate violence.”

Dulon said Morales might be looking to block solutions and eventually return to pacify the country as a hero — the path taken in 2002 by Venezuela’s then-president, Hugo Chávez, a Morales ally who was ousted by the opposition for two days and then returned to the presidency stronger than ever.

Many Bolivians still support Morales, Dulon said, and believe he was the victim of a coup.

Morales, 60, Bolivia’s first indigenous president, was credited with lifting Bolivians out of poverty during nearly 14 years in office. But he was accused of increasing authoritarianism against opponents and the news media.

He was seeking a fourth term as president, more than the Bolivian constitution allows. He called a referendum that would have allowed him to sidestep the limit and narrowly lost but then secured a court ruling that enabled him to run.

Morales portrayed himself Wednesday as a victim of political racism.

“I don’t understand how my commanders could be so disloyal,” he said. “My big crime is to be indigenous.”

He said he would return to Bolivia.

“Of course, if my people ask me, I’m willing to come back and pacify, but the national dialogue is important,” he said. “Of course, we will come back eventually.”