A widespread blackout plunged Chile\'s capital and other regions into darkness due to a problem with the national power grid, the Chilean emergency service said. Four of the South American nation\'s 15 regions -- including the Santiago capital area of more than six million people -- lost power around 2030 local time on Saturday (2330 GMT). Authorities gave no immediate explanation of the cause of the blackout. There were no immediate reports of related injuries. But the blackout ground the capital\'s subway system to a halt, cut off cellular phone service and forced the cancellation of a concert by Puerto Rican pop star Ricky Martin. Some areas of the capital regained power 50 minutes into the blackout, local radio reports said. The last massive blackout hit Chile in March 2010. Authorities said the national power grid would remain unstable for at least two years after the magnitude 8.8 earthquake in February 2010 that rocked Chile and killed more than 500 people.