Two people were shot to death Saturday during a confrontation between supporters of President Hugo Chavez and his opponent in next month's presidential election, Henrique Capriles, Venezuelan authorities said.

Justice Minister Tarek El Aissami said the shooting happened when loyalists of both candidates faced off on a road between the communities of Barinas and Barinitas in the country's central plains, about 450 kilometres southwest of Caracas, the capital.

The justice minister, who described the bloodshed as an "isolated incident," said police were looking for the shooter and trying to determine what led to the confrontation.

Speaking in a telephone interview broadcast by state-run Venezolana de Television, Aissami did not say anything about the dead men's political affiliation. But opposition officials said both were participants in a motorcade of Capriles supporters.

Opposition lawmaker Julio Cesar Reyes said a group of Chavez supporters blocked the caravan and people on both sides were arguing when a man appeared with a gun and started shooting.

Neither Aissami nor the opposition speculated on who the shooter might be.

Clashes have erupted previously during the campaign for the Oct. 7 presidential election, but these were the first deaths tied to a political event.

At least 14 people were injured Sept. 12 during stone throwing that broke out after Chavez backers blocked a road trying to prevent Capriles from reaching a campaign event in the central city of Puerto Cabello.

In July, Chavez supporters threw rocks at opposition supporters who were accompanying Capriles in a march through a poor Caracas neighbourhood. In March, shots rang out while Capriles was visiting a Caracas district that traditionally has been pro-Chavez and an opposition supporter was wounded.

Capriles, a former state governor, is considered the most serious rival that Chavez has faced since he was first elected president in 1998. The president is seeking another six-year term.