Political divisions appear to have deepened in Bolivia after four provinces controlled by the opposition put forward plans for greater autonomy from the central government.
The move comes as large rallies were held in the country both in support and opposition of Evo Morales, the president.
Thousands of Morales supporters marched through the city of La Paz to celebrate the unveiling of a new constitution that has divided public opinion in the country.
"This is a historic day ... the people will never again be marginalised," Morales told crowds outside the presidential palace after the president of the constitutional assembly submitted a copy of the new charter.
Morales accused his opponents of seeking to split the nation. "We're not going to let anyone divide Bolivia," he said.
The president has said a declaration of autonomy in the eastern city of Santa Cruz is illegal and unconstitutional.
Led by the economic hub of Santa Cruz, the four provinces oppose the new constitution and made separate declarations of autonomy to extend the power of their regional governments.
A Santa Cruz "autonomy statute," which voters in the state would have to approve in coming months, would create a separate police force and insist on state control of lands.
In Santa Cruz, hunger strikers called off their days-old protest against the constitution and headed to a city park for a rally to celebrate the declaration of autonomy.
A similar event was staged in natural gas-rich Tarija, and others were planned in the Amazon provinces of Beni and Pando.
"We're going to celebrate the birth of the autonomous regions," Roberto Gutierrez, a pro-autonomy leader in Santa Cruz, said.
The constitutional reform has deepened long-standing divisions between the more affluent east and the highlands, where the indigenous population strongly supports Morales, the country's first leader of Indian descent.
Leaders of the four lowland regions, home to Bolivia's natural gas fields, have called the new constitution an illegal power grab since it was passed by Morales supporters during an opposition boycott.
"In no way do we accept that the text that's being submitted represents the Bolivian people, because not all Bolivians have taken part in its drafting," Lourdes Millares, an opposition member of parliament, said.
Tensions rose ahead of Saturday's declarations of autonomy and Morales, has ruled out declaring martial law but government officials have said he could use force if any attempt is made to divide the country.
It was unclear whether the autonomy declarations would be ratified in provincial referenda.
The new national constitution, which lets presidents seek two consecutive terms and increases the state's role in the economy, must still pass two referenda to take force.
Morales says the constitutional rewrite will empower the poor, Indian majority.