Tokyo stocks tumbled further Tuesday, with the Nikkei index shedding more than 14 percent at one point on panic selling triggered by fears over deepening troubles at a quake-hit nuclear power plant.

The 225-issue Nikkei Stock Average fell 1,015.34 points, or 10.55 percent, to close at 8,605.15 after falling to as low as 8,227.63, the lowest since April 1, 2009, on an intraday basis.

It is the first time the index has ended more than 1,000 points lower since Oct. 16, 2008, when the stock market was hit hard by the collapse of Lehman Brothers Holdings Inc. in the previous month.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange plunged 80.23 points, or 9.47 percent, to 766.73.

All 33 sectors on the TSE took a battering, with the electric and gas sector leading decliners, followed by the iron and steel and real estate sectors. Of the decliners, the insurance sector had the smallest loss.

After hitting the day's low in the afternoon, stocks trimmed some of the lost ground. But declines remained steep as investors fled from assets considered risky on reports of further malfunctions at a nuclear power plant in Fukushima Prefecture.

"It all started with concerns over the safety of the nuclear power plant," said Fumiyuki Nakanishi, general manager at SMBC Friend Securities Co., adding that stock markets around the world were being affected by news of the nuclear crisis in Japan.

Increased radiation levels were detected in Tokyo's vicinity after a reactor container at the stricken power plant suffered damage.

Nakanishi further warned that the nuclear crisis is not the only factor weighing on the market.

"Even if the nuclear power plant woes calm down, if the power outage by Tokyo Electric Power lasts for a half year or longer, its impact on the Japanese economy is unimaginable," he said.

Power outages in the greater Tokyo and other areas have disrupted transportation and forced suspension of corporate activities, further souring market sentiment, brokers said.

Nuclear power-linked shares were sold, with Tokyo Electric Power Co. falling by the daily allowable limit of ¥400, or 24.7 percent, to ¥1,221.

Toshiba Corp., which delivered nuclear plant facilities at the troubled plant, closed down ¥80, or 19.5 percent, to ¥331, also down by the daily limit.