"I am not ready to prolong this shameful comedy we are in," the president said, as widespread protests, including attempts to cut Bolivia's gas and electricity supplies, entered their second week.

Bolivia's constitution allows Congress to vote to keep Mesa in power even if he submits his resignation.

If lawmakers accepts Mesa's resignation, Senate president Hormando Vaca Diez is next in line for the job, because the post of vice president is vacant.

Mesa, 51, came to power in October 2003, after president Gonzalo Sanchez de Lozada was toppled by street demonstrations, which killed as many as 80. Mesa, an intellectual and historian, was vice president at the time.

He has since attempted to resolve differences between business, agricultural workers and labor unions in this small landlocked nation of nine million, the poorest in Latin America.

His popularity stands at 60 percent, but the crisis continues to roil.

The opposition has been pressing for nationalization of the energy sector, business leaders in resource-rich Santa Cruz province have been demanding autonomy, and growers of coca, from which cocaine is extracted, have joined with labor unions in opposing economic measures they say impact them unfairly.

Hundreds of people rallied outside the presidential palace late Sunday in a show of support for Mesa, who acknowledged them by twice appearing on a balcony and later riding through the city by car.

"Mesa, we love you. The people are with you," chanted emotional crowds comprised largely of young people and women.

Bolivians also turned out for Mesa in the cities of Cochabamba and Sucre, while in the capital political leaders rallied behind the president.

Leaders of the third and fourth largest factions in Congress called for Mesa to remain in power through the end of his mandate, in August 2007.

But the president is locked in a political battle with opposition leader Evo Morales, head of the coca growers and the Movement Toward Socialism (MAS), the country's second-largest force in Congress.

Morales is leading the protests to pressure Congress to pass a new energy law that would raise royalties paid by multinationals from 18 to 50 percent.

Twenty-six companies including Total (France), Petrobras (Brazil), British Gas (Britain), Exxon Mobil (US), Repsol (Spain) and Plus Petrol (Argentina) risk seeing their contracts in Bolivia cancelled if the law is passed.

Morales, who lost the presidential election to Sanchez de Lozada in 2002 and later led the protests that toppled him, is also seeking a constitutional convention to "found the country anew."

He called Mesa's televised message "very aggressive, very provocative toward the indigenous movement."

"This resignation is simply for blackmail, a resignation so that nothing changes," Morales said.

Since last Monday, protesters have been on strike in El Alto, where the international airport serving La Paz is located. They have cut roads from La Paz to the interior of Bolivia and to Argentina, Chile and Peru, demanding the expulsion of Aguas de Illimani, a subsidiary of the French firm Suez Lyonnaise des Eaux.

On Saturday, Bolivia deployed the army's 9th Division and police to oil fields to stop protesters from taking over gas installations and electrical plants.

A top energy official said the Chaco oil company had shut down gas pumping and liquefying operations in the Bulo Bulo field.

The operation feeds the Bulo Bulo electricity plant, which in turn supplies the national electricity grid. However, the official said that the electricity supply would not be cut.

Mesa vowed not to use force to open highways, after the use of force by Sanchez de Lozada two years ago turned deadly.

"Here there will be no deaths," he said.

Sanchez de Lozada was toppled after trying to implement a plan to sell Bolivian natural gas, one of the largest reserves in South America, to the United States.

The plan to build a five billion dollar pipeline through Chile, an old foe of Bolivia, sparked a nationalist backlash in 2003, leading to his ouster.