Bolivian President Evo Morales has accused the rightist opposition of trying to divide the country with their call for a regional strike in protest over his plans to reform the constitution.
Opposition party Podemos and leaders from the South American nation's richer regions called a 24-hour general strike for Friday, posing the biggest challenge to Mr Morales since he became Bolivia's first president of native descent in January.
Opposition leaders have also threatened to abandon the national assembly that took office last month. The parliament has been given the job of rewriting the constitution, a measure Mr Morales says will empower the poor indigenous majority.
"We want a profound, democratic... change, and those people who want to abandon [the assembly] like Podemos have their own interests," Mr Morales told a news conference, following the strike call by four regions and Podemos leaders.
"We call on the Bolivian people to defend democracy and ... we call on the armed forces to assume their constitutional role to defend sovereignty and the national territory," he added.
Mr Morales' critics have accused his plans for the assembly of being totalitarian. His allies hold the majority of its 255 seats and the opposition says that if a simple-majority voting policy is allowed - as the government favours - they will boycott the process.
Added to the dispute over voting rules, opposition leaders are unhappy at the ruling party's aim to write a new constitution giving greater power to the masses.
Mr Morales has in turn accused Podemos of seeking to scupper his plans to transform South America's poorest country into a more prosperous and inclusive nation.
Debates at the assembly have been adjourned several times since it first went before parliament on August 6th.
Since Morales took office, demands for greater regional autonomy from the lowland regions of Santa Cruz, Beni, Pando and Tarija - where the strike is due to take place - have gained strength.
Santa Cruz is the country's economic powerhouse while Tarija is rich with natural gas.
Mr Morales was elected in December 2005 on a platform of nationalisation of natural resources, land redistribution and support for coca leaf production.
Establishing a constitutional assembly was one of the key demands of the social groups that toppled two presidents between 2003 and 2005 with mass protests.