La Paz, Bolivia CNN  — 

Bolivian Sen. Jeanine Anez declared herself the country’s acting leader Tuesday, despite a boycott by former President Evo Morales’ allies that left the legislative chamber short of the legal minimum number of lawmakers required to appoint her.

Anez said she would become interim president after the three people ahead of her in the line of succession quit in the wake of massive protests following Morales’ resignation.

Morales, who has fled to Mexico, says he was forced to resign by the military and claims he is the victim of a coup. He has vowed to continue fighting from abroad.

In Morales’ absence, members of his leftist political party were a no-show at the legislative session to appoint Anez, the second vice president of the Senate, leaving the chamber without a quorum to do business.

Jeanine Anez, center, declares herself Bolivia's interim president during a Congress session.

In a tweet, Morales called Anez’s assumption of the presidency “the most crafty and disastrous coup in history.”

“We are here safe thanks to Mexico and its authorities, but I also want to tell you sisters and brothers, as long as I’m alive, we’ll continue in politics,” he said.

Supporters of Morales flooded the streets of the administrative capital, La Paz, to support the former President, and did so mostly peacefully.

Bolivia has been rocked by violent protests since the country held elections on October 20. Opposition politicians accused electoral authorities of manipulating the results of that contest in favor of Morales, who had been president for nearly 14 years. Morales denied the allegations and declared himself winner.

A military armored vehicle patrols as supporters of former President Morales march in La Paz.

Morales pledged Sunday to hold new elections after monitors from the Washington-based Organization of American States (OAS) published a report alleging voting irregularities. The head of Bolivia’s armed forces, Cmdr. Williams Kaliman, asked Morales to step down in order to restore stability and peace on Sunday.

Morales appeared to accede to those demands by resigning, but then later claimed he was forced to do so.

The longtime leader – and first indigenous Bolivian elected President – was granted political asylum by Mexico, but it took him some time to arrive in the country.

The Mexican Air Force plane sent to pick up Morales was initially denied access to Bolivian airspace, takeoff was delayed and protesters surrounded the airport. After Morales boarded the plane, it was denied permission to refuel in Peru. It had to stop in Paraguay before arriving in Mexico City.

Upon landing, Morales thanked Mexican President Andres Manuel Lopez Obrador for saving his life and reiterated that he had been forced to resign.

Anez (center), a member of the Democratic Union Party and second vice president of the Senate, after she declared herself as interim President.

Lopez Obrador and Morales’ left-leaning allies in Latin America have backed the former president’s allegations of a coup, but the opposition in Bolivia said the country was instead engaged in a fight for “democracy and peace.”

Brazil’s Foreign Ministry said Tuesday it rejected the “thesis that a ‘coup’ is taking place in Bolivia,” suggesting instead that Morales was “delegitimized” by popular protests following an “attempt at electoral fraud.”

US Secretary of State Mike Pompeo said in a statement that Washington commended the OAS mission that found the electoral irregularities and backed calls for a new vote.

Former Bolivian President Evo Morales waves upon his arrival in Mexico City on Tuesday.

A senior State Department official said at a briefing Monday that the US does not believe Morales was overthrown illegitimately.

“You have surely seen statements by Morales and his supporters calling him the victim of a coup, despite the fact that what all these events clearly show is the Bolivian people have simply had enough of a government ignoring the will of its voters,” the official said.

“And continued incitement and unrest and violence to feed this false narrative is simply damaging Bolivian democracy.”

On Wednesday, the United Kingdom congratulated Bolivia’s acting president for “taking on her new responsibilities as interim President of Bolivia.”

“We welcome Ms Anez’s appointment and her declared intention to hold elections soon. Free and fair elections will rebuild confidence in democracy for the Bolivian people,” the UK Foreign and Commonwealth Office said in a statement.

CNN’s Natalie Gallon, Tatiana Arias and Julia Jones contributed to this report