ROME - Power went out across Italy before dawn Sunday, plunging the nation into darkness, police and news reports said. Authorities did not immediately know the cause.

There was no official tally of customers without power, but early reports indicated most of Italy's 58 million people could be affected. The Aug. 14 blackout in the eastern United States affected 50 million people.

The first Italian power outages were reported around 4 a.m. local time in Rome, where the city was celebrating an all-night festival with museums and restaurants open around the clock.

Later, the national electricity company ACEA said power was out across the nation, the ANSA news agency said.

"As far as we know it's all across Italy," police official Franca Sesti Miraglia said in Rome.

"We don't know the cause yet," she said.