The chief mediator in talks between Venezuela's government and the opposition says violence could break out unless the sides reach an agreement.

The secretary-general of the Organization of American States, Cesar Gaviria, says both parties continue to have differences, but he urged them to continue efforts to resolve the political crisis.

Mr. Gaviria said Wednesday he was fearful the longer the crisis continues, the greater the possibility for violence. Negotiations are continuing Thursday.

A general strike in Venezuela is now in its 11th day. The stoppage halted oil exports, but the government said Wednesday it regained control of the vital industry.

Speaking in Caracas, Energy Minister Rafael Ramirez said an oil tanker departed for the United States and four other vessels were being loaded.

He also said the government has broken what he called a "blockade" and is exporting oil, while an official at the state-owned oil company says no tankers have left Venezuelan shores.

The general strike, aimed at ousting President Hugo Chavez, has created shortages of food, drinking water and cash.

The government says the work stoppage is costing $50 million per day in Venezuela, the world's fifth-largest oil exporter.

Three people were killed last week when a gunman opened fire at an opposition rally. Protests also turned deadly in April when snipers opened fire on demonstrators. The deadly rioting led to a brief ouster of President Chavez.