(AFP) - A deputy senate speaker proclaimed herself Bolivia's new interim president Tuesday as Evo Morales' opponents sought to end civil turmoil and fill the power vacuum left by his abrupt resignation as president.

Lawmakers had been summoned to formalize Sunday's resignation and confirm Jeanine Anez, 52, as interim president.

Instead, Anez declared herself interim president when the session failed to reach a quorum of lawmakers, many staying away amid blockades and continuing protests by Morales supporters.

Although lawmakers did not reach a quorum, the Constitutional Court later endorsed her appointment.

"We want to call new elections as soon as possible," Anez said in a speech to Congress, with only Morales opponents present.

"It's a commitment we have made to the country and of course, we will fulfill it," she said.

Later, clutching a bible and wearing the presidential sash over her black jacket, the senator addressed supporters from the balcony of the government palace.

Anez said earlier Tuesday she was confident that enough senators would reach the Senate to form a quorum -- 19 of the 36 were needed to do so.

Morales, tweeting from exile in Mexico, immediatly condemned what he called "the sneakiest, most nefarious coup in history."

Morales called Anez "a coup-mongering right-wing senator" and said she had "declared herself... interim president without a legislative quorum, surrounded by a group of accomplices."

Leaders of the biggest party, Morales' Movement for Socialism (MAS) had requested guarantees to be able to attend the session, but stayed away.

- New clashes -

Security forces fired tear gas in street clashes in La Paz immediately after the Congress session.

Carlos Mesa, the centrist candidate defeated by Morales in the tainted October 20 presidential elections, tweeted his congratulations to Anez, who has promised a new government would be installed by January 22.

Powerful opposition figure Luis Fernandez Camacho, regional leader in eastern department of Santa Cruz, announced he had lifted strikes and blockades called three weeks ago in protest at Morales' disputed re-election.

Morales resigned after losing the support of the military, leaving the country suddenly rudderless. Dozens of officials and ministers also stepped down, some seeking refuge in foreign embassies.

Anez found herself next in line to take over after the resignations of vice president Alvaro Garcia Linera, the Senate president, and the speaker of the lower house of Congress.

- 'Struggle' continues -

Earlier Tuesday, Morales vowed to continue "the struggle" after arriving in Mexico where he has been granted political asylum.

Morales thanked left-wing ally and Mexico President Andres Manuel Lopez Obrador, saying "he saved my life," and vowed to remain in politics despite having left his homeland.

Grinning and waving as he left the Mexican military plane that had picked him up from Bolivia late on Monday night, Morales was welcomed by Foreign Minister Marcelo Ebrard.

Morales said in a speech that he was victim of a "coup", and defended his record on improving living conditions for poor and indigenous Bolivians.

He said "there will only be peace when social justice is achieved for all."

On Monday, the armed forces pledged to help police take back the streets from violent groups that have wreaked havoc since the controversial October 20 election that saw Morales win an unconstitutional fourth term.

Security forces deployed in La Paz on Tuesday, where Morales supporters marched through the center to congregate in San Francisco Square near the Congress.

Burning barricades manned by opposition protesters were also preventing access to the Congress.

- Mexico steps in -

Morales asked left-wing ally Mexico for asylum and was whisked away on a military plane, along with his son and Garcia Linera. It made a stop in Paraguay to refuel and file a flight path to Mexico.

The crisis touched off by Morales's resignation on Sunday -- after three weeks of protests over his disputed re-election -- deepened on Monday as gangs unhappy with his departure attacked police stations and civilians, triggering panic in the streets.

Three people have died in clashes since the election.

Morales, 60, a former coca farmer who was Bolivia's first indigenous president, said his opposition rivals, Mesa and Luis Fernando Camacho, "will go down in history as racists and coup plotters."

He was Latin America's longest serving leader until Sunday.

Morales had initially tried to hold onto power and call new elections following an Organization of American States audit that found "irregularities" in virtually every area reviewed and questioned "the integrity of the election results."

© Agence France-Presse