SEOUL - Under a mock scenario, a train stopped operating due to a blackout and its passengers were trapped inside and had to be extricated.

It was part of a nationwide drill held in South Korea on Thursday, aimed at raising the public's awareness against possible power outages during the peak summer season.

Authorities, who came to the rescue of the passengers, opened platform screen doors and helped them get out of the train.

People who got stuck in a stalled elevator during the blackout were also rescued and carried away from the scene for medical treatment.

Citizens who took part in the drill mostly gave a positive note to the government's latest measure to prevent a massive power outage like the one that affected nearly two million homes nationwide in September last year.  "If we continue to do this drill actively, it will be a good practice for energy saving and Earth conservation," said Park Hee-jung, a 43-year-old Seoul resident.

Thursday's drill was conducted under the possibility that the country's electricity reserves could fall below two million kilowatts.

During the 20-minute exercise, households were encouraged to voluntarily participate in power saving efforts by switching off air conditioners and electric fans and suspending the use of irons, vacuum cleaners, washing machines and electric ovens.

Industrial facilities were asked to reduce energy consumption during the exercise as much as possible, while electricity to public buildings and schools were cut off except for essential security equipment.

Power supply to 28 selected buildings in seven major cities was cut to check their readiness for potential power blackouts.

Facilities vulnerable to power cuts, such as elevators, subway stations and hospitals, carried out emergency response training.

Earlier this month, South Korea's electricity reserves fell below the country's threshold of four million kilowatts, sparking fears that it might experience another blackout since September last year.