About 90 percent of Chile's power has been restored after a massive blackout hit much of the country. The failure of a transformer on a main power grid in central Chile, was believed to be the primary cause of the blackout.

Chilean pop singers and musicians are performing at a benefit concert for quake victims.

But a blackout suddenly turned the venue into total darkness.

Chileans were already anxious after last month's earthquake and after the sudden outage, people were running out of homes, subway stations and theaters in panic. Police patrolled the streets in order to give residents a sense of security.

Ricardo Rainieri, Chilean Energy Minister, said, "Sadly we had an drastic cut in the electricity supply, let's say it has affected the central transmission system. This situation could be related to a collateral effect from the February 27th earthquake, when the electrical system was left in a very fragile state. It will be gradually repaired in the coming months."

One hour after the incident, lights began to come back on in some cities. But the Interior Minister said a few more hours were needed for a full restoration.

Rodrigo Hinzpeter, Chilean Interior Minister, said, "We can't anticipate a time for power to be fully restored, but we can anticipate with full confidence, that we are working very hard to make it happen as soon as possible."

More than 80 percent of Chile's 17 million people were affected by the blackout.

The areas affected include the southern regions of Maule and Bio Bio, two of the hardest hit regions in February's devastating earthquake.

The local fire department said so far, there were no reports of casualties related to the blackout.