Photo: The Canadian Press

Clashes broke out in the streets of Bolivia's capital Tuesday evening when an opposition leader in the Senate declared herself the country's interim president after Evo Morales fled to Mexico following his surprise weekend resignation.

Jeanine Añez claimed the post of Senate leader late in the day, a position next in line for the presidency, even though she lacked a quorum because of a boycott by Morales' Movement for Socialism party. Without being sworn in by anyone, she then appeared on a balcony of the old presidential palace wearing the presidential sash and holding a Bible in her hand.

"My commitment is to return democracy and tranquility to the country," she said. "They can never again steal our vote."

It was uncertain how much support Añez could count on from other power centres in her bid to replace Morales, who stepped down Sunday under pressure from Bolivia's military following weeks of violent protests fed by allegations of electoral fraud in the Oct. 20 presidential election.

Some Bolivians quickly took to the streets cheering and waving national flags in opposition strongholds like the cities of Santa Cruz and Cochabamba, but angry Morales' supporters tried to reach the Congress building in La Paz screaming, "She must quit!" Police and soldiers fired tear gas trying to disperse the crowd and detained some demonstrators.

Morales, who sought to transform Bolivia as its first indigenous president, had faced weeks of widespread outrage over his claim to have won the election outright. He stepped down soon after an Organization of American States audit reported widespread irregularities in the vote count.

He arrived in Mexico on Tuesday under a grant of asylum. But his resignation still needed to be approved by both houses of Congress, and lawmakers could not assemble the numbers needed for formal sessions.

Añez, a 52-year-old lawmaker, women's rights activist and television presenter, forged ahead anyway, arguing that Bolivia could not wait and be left in a power vacuum. After Morales quit, resignations by allies left vacancies in the only posts listed by the constitution as presidential successors — the vice-president, the head of the Senate and the leader of the lower house.

Añez was a second-tier opposition figure until Morales resigned Sunday after nearly 14 years in power, the longest presidential reign ever in Bolivia.

From the start, she tried to set differences with the socialist leader. She greeted supporters at an old palace instead of the nearby modern 26-story presidential palace with a heliport that was built by Morales and that his foes had criticized as one of his excesses. She also carried a Bible, which had been banned by Morales from the presidential palace.

Morales said on Twitter from Mexico that Añez's "self-proclamation" was an affront to constitutional government. "Bolivia is suffering an assault on the power of the people," he wrote.