Spain and Portugal were hit by a widespread power blackout on April 28 that paralyzed public transport, caused large traffic jams and delayed airline flights, and utility operators were scrambling to restore the grid.
Authorities were unable to explain the cause of the outage at least an hour after it occurred, though a possible cyber attack had not been ruled out and investigations were ongoing, officials said. A crisis committee was set up in Spain to manage the situation, according to people familiar with the situation.