Another problem has hit a badly damaged nuclear power plant in northeastern Japan, where a powerful explosion occurred on Saturday.

The emergency cooling system at the No. 3 reactor at the Fukushima nuclear plant stopped functioning on Sunday, requiring engineers to pump water to cool the plant's reactor in attempt to avoid a meltdown at the site, Reuters reported.

Experts say that a large number of people in affected areas would suffer from acute radiation syndrome and there would be a rise in specific types of cancers and stillbirths if a full meltdown occurred.

There are concerns that the death toll from Friday's catastrophic 8.9-magnitude earthquake in Japan could exceed 1,800.

The strong tremor has left millions of people in the quake-stricken area without water, gas, and electricity.

The quake struck at 2:46 p.m. local time (0546 GMT) on Friday and its epicenter was monitored at about 373 kilometers (231 miles) from the capital Tokyo, with a depth of 32 kilometers (20 miles).

The temblor triggered a seven-meter (23-foot) tsunami and was followed by over 50 aftershocks over the next few hours, with many measuring more than 6.0 on the Richter scale.

On Friday, Japanese Prime Minister Naoto Kan pledged that the government would do all it can to rescue the survivors of the disaster.

The Japanese islands are located in an area that is the convergence point for several continental and oceanic plates. Because of Japan's location on an active plate zone, the country has had a long history of serious quakes.

The worst earthquake to hit Japan was the 8.3-magnitude Great Kanto Earthquake of 1923, which killed 100,000 people.

In 1995, the city of Kobe was hit by a powerful earthquake that killed 6,000 and injured nearly half a million residents.