A political crisis in Bolivia was Friday moving towards confrontation after President Evo Morales announced a referendum on a new, socialist constitution in the teeth of fierce opposition from rebel conservative governors.

Morales, the first indigenous leader of the impoverished South American nation, late Thursday declared the referendum would be held December 7 to "deepen democracy" and "to consolidate the process of change."

The plebiscite will seek to give more national revenues to the country's downtrodden indigenous majority, an estimated 60 percent of the 10-million strong population, and put a cap of the size of large land holdings.

It will also enshrine expropriation laws Morales has used over the past year to nationalize companies in the gas and telecommunications sectors.

The announcement of the vote was widely expected, after Morales won two-thirds support for his mandate in an August 10 recall referendum.

That plebiscite also confirmed most of his gubernatorial foes in their jobs, however, and worsened a stalemate that has left Bolivia increasingly ungovernable.

The conservative governors of five of Bolivia's nine states -- all of them located in the low-lying eastern half of the country where huge farms and gas fields vital to the economy are concentrated -- have already said they will prevent the referendum being held.

They challenge the legality of the draft revised constitution, which was adopted by congress in December with most opposition lawmakers absent.

The governors are also making moves towards autonomy in their states of Santa Cruz, Beni, Tarija, Pando and Chuquisaca, and are demanding more control over gas revenues.

Sometimes violent anti-government protests in opposition areas recently have prevented Morales from visiting. On Wednesday, his helicopter was forced to land in neighboring Brazil after it ran low on fuel over one such area.

Morales ordered troops to secure oil and gas facilities in the east of the country last weekend, as opposition demonstrations stepped up into strikes and roadblocks.

On Friday, Morales left for a four-day trip to Libya and Iran, reinforcing newly formed diplomatic ties with the two oil powers.

One of the main opposition figures in congress, former conservative president Jorge Tuto Quiroga, accused Morales of governing in the authoritarian style of disgraced Peruvian former president Alberto Fujimori or Venezuelan President Hugo Chavez.

Thursday's decree setting up the December 7 referendum "is a trampling of democracy," Quiroga said, and urged "Bolivian citizens to mobilize in a civil resistance to avert division and confrontation."