MADRID: A huge power outage brought Spain, and parts of Portugal and France to a standstill on Monday, grounding planes, halting public transport, causing panic buying and leaving the authorities scrambling to restore power to millions of homes and businesses.

Hospitals halted routine work, shops shut their doors and the governments of Spain and Portugal convened emergency cabinet meetings as officials tried to find out what caused the mass blackout from around 1033 GMT.

Outages on such a massive scale are extremely rare in Europe.

`We do not yet have conclusive information on the reasons for this (power) cut, so I ask the people, as we have done in past crises, to inform themselves through official channels,` Spanish Prime Minister Pedro Sanchez said in a national address.

`For the time being, there`s no evidence of any civil protection problems. I repeat, there are no problems of insecurity.

Hospitals in Madrid and Cataluna in Spain turned to generators for critical patients. Some oil refineries were shut down and retail businesses closed in both countries. The Bank of Spain said e-banking was functioning `adequately` on backup systems, though residents reported ATM screens went blank.In Lisbon, electricity grid operator in the afternoon said it is `still impossible to know` how long Portugal will be without power after the massive blackout that also affected Spain and parts ofFrance.

The French grid operator, however, said it had moved to supplement power to some parts of northern Spain after the outage hit.

Gridlock Spanishradio stations said part of the Madrid underground was being evacuated, and play at the Madrid Open tennis tournament was suspended.

There were traffic jams in Madrid as traffic lights stopped working, with people in reflective vests standing at intersections to direct traffic.

Hundreds of people stood outside office buildings on Madrid streets.

A building housing the British Embassy had been evacuated, the witness added.

Images from a Madrid supermarket showed long queues and empty shelves as people rushed to stock up on staples.

Local radio reported people trapped in stalled metro cars and elevators. Police said traffic lights were affected across Portugal, the metro was closed in Lisbon and Porto. Lisbon`s subway transport operator said the subway was at a standstill. Lisbon airport was running on generators, while AENA, which manages 46 airports in Spain, reported flight delays around the country.-Agencies