A German power company says its disconnection of a high-voltage transmission line may have triggered the chain-reaction electrical outages that hit about 10 million people in central and western Europe late Saturday.

Germany and France were hit worst. Parts of Italy, Belgium, Austria and Spain were also affected. Power failed first in Cologne, Germany, before outages were reported elsewhere.

The private German electric company, E.On AG, said Sunday that the problem began in its network in northwestern Germany, possibly after it disconnected the line to allow a ship to pass safely on the Ems River.

The company said its network may have became overloaded, but stressed the cause was still under investigation.

The power was only down for anywhere from a few minutes to 1½ hours in most regions, halting trains and trapping some people in elevators, but causing no injuries.

The cascade of blackouts has raised new questions about the reliability of Europe's interconnected power grids. Italian Prime Minister Romano Prodi said Europe should have a central authority to oversee the entire network.

The last major power outage to affect Europe struck Italy in September 2003, plunging nearly the entire country into darkness for 18 hours. The problem was traced to a short in a power line in Switzerland.

A similar incident occurred in much of Ontario and the northeastern United States in August 2003, when tree limbs touching a power line in Ohio triggered a massive blackout. Electricity was cut to 10 million people in Ontario and another 40 million in the U.S. for about 24 hours in most affected areas.

With files from the Associated Press