La Paz, Bolivia ? Bolivia’s new president promised early elections and worked Saturday to form a transition government as his predecessor fled to the United States, driven from office by a month of violent demonstrations.

President Carlos Mesa — the former vice president inaugurated late Friday after Gonzalo Sanchez de Lozada resigned — takes over this struggling Andean nation amid its worst crisis in decades and after rioting that left 65 people dead.

“We have to respond to one of the biggest challenges in our history. If you all can’t help me there is no way we can crawl out of this,” the new president said late Friday.

Mesa, 50, conducted talks at his home Saturday with labor and government officials, and said his administration would be an interim one, even though law calls him to serve out the rest of the ex-president’s term, until August 2007.

The departure of the 73-year-old Sanchez de Lozada brought a degree of peace: Soldiers and police withdrew early Saturday from streets in the capital, La Paz, and other cities. Merchants and vendors reopened for business. Governments around Latin America offered support for Mesa.

Still, Mesa inherits a climate of social unrest over the ex-president’s free-market economic policies, seen as widening the divide between rich and poor. Unemployment is at 12 percent and most Bolivians earn about $2 a day.

Poor Bolivians — Indian and labor leaders — spearheaded the street demonstrations that started in mid-September and swelled into marches by thousands. People built road blocks that caused food shortages and isolated La Paz from the rest of the country. Protesters with sticks and rocks clashed for days with soldiers sent to drive them away.

The riots erupted over Sanchez de Lozada’s plan to export natural gas to Mexico and energy-starved California. The ex-president had hoped to tap the country’s expansive natural gas reserves to boost economic growth and lift South America’s poorest country out of years of economic stagnation.

Many Bolivians were particularly angry that the fuel might be shipped through a port in neighboring Chile instead of through Peru, another option. Bolivia lost its coastline in an 1879 war against Chile, and resentment is fierce to this day.

Bolivian President Carlos Mesa greets the crowd at El Alto near the Bolivian capital, La Paz. The new leader began talks with political and labor leaders Saturday, rushing to form a transition government after weeks of violent anti-government protests forced his predecessor from power.

Meanwhile, the disgraced ex-president sought refuge in the United States, where he was raised and educated, amid concerns for his security in Bolivia.

The U.S. State Department had no immediate comment on his arrival in the United States.

Abandoning the presidential residence in a helicopter, Sanchez de Lozada became the fourth Latin American president driven from office by widespread protests in recent years.

Ecuador’s Jamil Mahuad, Peru’s Alberto Fujimori and Argentina’s Fernando De la Rua were all unseated by outpourings of anger over U.S.-backed free-market economic policies.