Bolivia will slide into civil war unless immediate elections are held, President Carlos Mesa has warned, a day after he offered to resign from office.
Protesters and police were locked in battle on the streets of La Paz
The main city La Paz has seen violent clashes between security forces and protesters calling for economic reform and more rights for indigenous people.
Correspondents say Mr Mesa's offer to resign seems to have emboldened the protesters, rather than pacify them.
Congress will meet on Thursday to vote on whether to accept Mr Mesa's offer.
In a televised address, Mr Mesa criticised Congress for delaying the vote until Thursday, and stressed that he would not revoke his decision to resign.
He also urged the leader of Congress, Hormando Vaca Diez, to forsake his constitutional claim to the country's presidency and call early elections instead.
Carlos Mesa made his second TV appearance in as many days
Mr Diez is legally entitled to take over the presidency if Mr Mesa's resignation is accepted, but is deeply unpopular with the protesters.
"The country can not continue playing with the possibility of splitting into a thousand pieces. The only solution for Bolivia is an immediate electoral process," Mr Mesa said.
"This is coming from a president who is on his way out. It is a call to a country on the brink of civil war," he said.
Anti-government demonstrators fought running battles with police in La Paz on Tuesday, continuing a campaign that began weeks ago and has almost paralysed the country.
The chaos in La Paz has prompted Congress to locate its Thursday session in the city of Sucre, 600km from La Paz.
Throughout Tuesday, poor Indian peasant farmers, miners and trades union members clashed with the police.
When they hurled deafening charges of dynamite, riot police responded with tear gas, forcing demonstrators and unlucky civilians to scurry for cover.
The protests erupted last month after a law was passed imposing taxes on foreign companies that have invested in Bolivia's gas reserves, thought to be the second-largest in South America.
The protesters said the law did not go far enough and called for the gas industry to be nationalised.
They also want constitutional reforms to give greater rights to the country's impoverished highlanders, most of whom are of indigenous descent.
They oppose demands from Bolivia's resource-rich eastern provinces for greater autonomy and more foreign investment.
Mr Mesa, who came to power 19 months ago after his predecessor was forced out by similar protests over energy, announced his resignation in a televised address on Monday after a day of mass protests.
Mr Mesa offered to quit during similar protests in March, but the offer was rejected by Congress.