A massive blackout left more than half of Venezuela without electricity on Friday afternoon, according to news reports.

The blackout affected as many as 13 Venezuelan states, leaving around 60% of the country without electricity, the local newspapers El Universal and El Nacional reported. A cut in the electricity line between San Gerónimo and La Arenosa in the state of Guarico was reportedly responsible for the outage.

"It seems like there are some problems, we are going to investigate the problems we are having with electrical service in some parts of the country," President Nicolas Maduro said in a speech, according to Reuters.

Venezuelans reported the outage, which left 2 million people in the capital Caracas without subway service, on Twitter.

Gran apagón afecta a la mayor parte de las ciudades de Venezuela pic.twitter.com/dCGSFwFHpC — Meli Colmenares (@MelCol_) June 27, 2014

#VENEZUELA #TROPA NI CON CHIABES PASABA ESTO; SON UNA VERGÜENZA ! APAGON EN MÁS DE LA MITAD DEL PAÍS ! pic.twitter.com/tpWDvHhNhb — michael scholz (@RaulDictador) June 27, 2014

This is not the first time the country suffers a major blackout. In December, Venezuela plunged into darkness.

It's unclear why electricity outages are so frequent in Venezuela. But critics say lackluster investment in the energy sector by the Maduro government is to blame.