Bolivia's new interim president pledged to hold new elections as soon as possible and condemned the acts of "revenge" perpetrated by disgruntled supporters of deposed leader Evo Morales, who resigned after protesting a disputed vote .

Senate Deputy Speaker Jeanine Áñez, 52, assumed the acting role on Tuesday night with a Bible in her hand after Morales fled to Mexico at the end of his 14 years of socialist rule.

"May God bless us and allow us to be free and hold transparent elections soon," she tweeted Wednesday in a message to young people in the country.

His arrival at the presidential palace faces an immediate challenge from lawmakers loyal to Morales, who hold a majority in parliament and who threatened to hold a rival session to cancel his appointment.

After weeks of violent protests against presumed election fraud, and then Morales' resignation, La Paz, the capital of the highlands, was quieter on Wednesday, though dozens of his supporters protested outside to seek out block access to the palace.

In the 48-hour weekend of unrest, the mutinied police joined the marches, the allies deserted Morales, the Organization of American States (OAS) declared that his reelection was being manipulated and the army had him asked to resign.

From Mexico, Morales remained provocative, tweeting that Áñez's "proclamation" was an affront to constitutional government. "Bolivia is undergoing an assault on the power of the people," he wrote.

Supporters, including a teachers' union, organized rallies for Morales, Bolivia's first indigenous president loved by the poor when he took power in 2006.

Opponents said that the pressure had reached a point of no return after having more and more evidence of an alteration of the October vote, and that Morales had opposed the will of the people by asking for a fourth term.

Supporters of former Bolivian President Evo Morales parade Wednesday during the demonstration between El Alto and La Paz.

Supporters of former Bolivian President Evo Morales parade Wednesday during the demonstration between El Alto and La Paz. Photo: Ronaldo Schemidt / AFP via Getty Images

The largest union in Bolivia has threatened to launch a general strike unless politicians can restore stability. A leader of the coca farmers' unions and a legislator close to Morales called for protests until his return to complete his term in January.

Áñez met Tuesday night with the police and the army, urging them to ensure peace.

"What a shame, revenge continues," she tweeted to one of the deputies who said that her house had been attacked by supporters of the Movement for Socialism of Morales (Mas).

Áñez, a conservative Christian, is a very different figure from Morales, who was the first indigenous president of Bolivia in modern times, and she immediately tried to stand out from her predecessor.

Wearing the presidential sash, she welcomed supporters into an old presidential palace instead of the 26-story modern presidency with a helipad built by Morales and that his opponents had criticized for being one of his excesses .

She also wore a Bible, which had been banned by the presidential palace by Morales after reforming the constitution and recognized the Andean deity of the land, Pachamama, instead of the Roman Catholic Church.

The Bolivian crisis has divided the international response, left-wing allies echoing its coup allegations and others applauding its resignation as beneficial to democracy.

Both Brazil and the United Kingdom, led by the Conservatives, congratulated Áñez.