MADRID/LISBON (Reuters) -A huge power outage brought parts of Spain and Portugal to a standstill on Monday, grounding planes, halting public transport, causing panic buying and leaving the two countries scrambling to restore power to millions of homes and businesses.

Much of Spain and Portugal have been hit by a widespread power outage that has canceled flights, brought trains to a halt, downed phone lines and cellphone networks.

A major power outage in Spain and Portugal has knocked out subway networks, traffic signals and ATMs. Spanish power distributor Red Eléctrica said resto