"The truth is that human lives have been lost, and that is irreparable," Javier Zabaleta told local media, following reports of violence in the eastern town of Montero in Santa Cruz department.

"The worst of all this is that if we, the politicians, do not seek a solution to this, what has happened now in Montero can be repeated not only in Santa Cruz, but in other parts of the country," the minister added.

The El Debe newspaper identified the two victims as being men aged 48 and 60, saying they had been shot.

A doctor at the Montero clinic confirmed to La Razon newspaper that "both died with the same characteristics... with weapons of the same caliber."

President of the opposition civil committee of Montero Regis Medina, who called a strike against the election of Morales, also reported that two people had been killed.

The killings came as Bolivia's government agreed to a binding audit by the US-based Organization of American States of the disputed election results, which awarded Morales a fourth term in office.

However, opposition leader Carlos Mesa, who was defeated by Morales in the vote, rejected the audit.

Angry opposition protesters have set up street barricades and gone on strike since the announcement of the results, fighting Morales supporters with bare hands and makeshift weapons.

Demonstrators have also clashed with security forces.

Mesa has called for strikes to continue and claimed that civic institutions and social movements supported his rejection of the official results.