Tokyo Electric Power Company Holdings Inc., operator of the wrecked Fukushima No. 1 nuclear plant, said first-quarter operating profit plummeted 37 percent as sales declined amid faltering demand and new competition in Japan's power market.

Tepco posted operating profit of ¥143.6 billion for the three months ended June 30, down from ¥228.3 billion a year ago, the company said in a statement Thursday.

Revenue fell about 18 percent to ¥1.26 trillion as the company's electricity sales volume dropped and rates were automatically lowered by the nation's price adjustment system. The system adjusts monthly electricity rates for each utility based on a three-month average of import prices for LNG, crude oil and coal.