Up to 40 percent of Venezuela was plunged into darkness for at least 15 minutes on Thursday as the country continues to address electricity supply problems.

The state-run National Electric Corporation (Corpoelec) said the blackout was due to failures at the country's biggest thermopower plant in Carabobo state and in the power supply systemin Vergara state.

Corpoelec president Hipolito Izquierdo said the failures had occurred at 1:15 p.m. (1745 GMT) and cut electricity supply to Caracas and 13 of the country's 23 states.

The affected states included Aragua, Barinas, Carabobo, Guarico,Lara,Merida, Miranda, Nueva Esparta, Portuguesa, Sucre, Tachira, Vargas and Zulia, according to the Corpoelec chief.

The 43-station Caracas Subway was stopped by the blackout and train services linking Caracas with Miranda was also affected, track transport authorities confirmed.

Izquierdo assured the public that power supplies were being re-established in most affected states.

Official figures have put Venezuela's 2009 electricity deficit at 4 percent and the Venezuelan government is investing to diversify electricity generation sources in the country, which currently gets 70 percent of its electricity from the Guri hydro dam.

Venezuela has already spent 3.1 million U.S. dollars on power diversification between 2008 and this year.

For the first time in 10 years, Venezuela encountered four big blackouts in 2008.

Source: Xinhua