Tokyo: To mark the three-month anniversary of the powerful earthquake and tsunami which triggered one of the world's worst nuclear disasters, protesters in Tokyo held mass demonstration on Saturday against the use of nuclear power.

The magnitude-9 earthquake that hit off Japan's northeast coast March 11 caused a massive tsunami that devastated the coastline.

The disasters knocked out power and cooling systems at the Fukushima Dai-ichi nuclear power plant, about 140 miles northeast of Tokyo, setting off explosions, fires and large radiation leaks at the facility.

Official reports released earlier in the week said the damage and leakage was worse than previously thought, with nuclear fuel in three reactors likely melting through their main cores and larger containment vessels.

The reports also said radiation that leaked into the air amounted to about one-sixth of the Chernobyl nuclear disaster in 1986.

Hundreds of plant workers are still scrambling to bring the crippled Fukushima reactors to a "cold shutdown" by early next year and end the crisis.

The accident has forced more than 80,000 residents to evacuate from their homes around the plant.

The disasters have renewed a national debate on the use of nuclear power in Japan, which has few natural resources and is heavily reliant on atomic energy.

Some nuclear plants across the country have been shut down in the wake of the disaster, leading to fears Japan may not have enough electricity for the peak summer months, and several anti-nuclear protests have been held.