Colombia's electrical grid collapsed Thursday, causing a nationwide blackout that halted trading on the stock exchange, trapped people in elevators and left authorities struggling to determine the cause.
Luis Alarcon, manager of state-controlled electricity distributor ISA, told Caracol Radio that the power outage appears to have begun with an undetermined technical glitch at a substation in Bogota and quickly spread to the rest of the country.
He said work crews had re-established power to about 20 percent of the country and hoped to reconnect the capital Bogota and other cities in a few hours.
There was no indication of a terrorist attack.
Leftist rebels routinely sabotage electric transmission lines as part of their four-decade old campaign to overthrow the government, but such attacks usually have a limited impact.