Tokyo stocks tumbled Monday, battered by mounting concerns over a further spread of pneumonia caused by a new strain of coronavirus from China.

The Nikkei 225 average dived 483.67 points, or 2.03 percent, to end at 23,343.51 after briefly losing over 500 points. On Friday, the key market gauge rose 31.74 points.

The Topix, which covers all first-section issues on the Tokyo Stock Exchange plunged 27.87 points, or 1.61 percent, to 1,702.57 after falling 0.06 point Friday.

A wide range of issues came under heavy selling pressure from the outset as investors rushed to reduce risk exposure out of growing fears about the spread of the pneumonia following reports of an increase in the number of infected patients and the death toll, brokers said.

Also weighed down by the yen’s strengthening against the dollar, both indexes stayed deep in negative territory throughout the session, brokers said.

“Investors harbor fears that a further spread of the pneumonia may stall economic activities in China, including industrial production and consumption, which in turn may lead to a slowdown in the Japanese and U.S. economies,” an official of an asset management company said.

“The outlook appears tough for Japanese stocks for the immediate future, at least until mid-February, with the new pneumonia spreading further, which will be a blow to the Chinese economy,” said Tomoaki Fujii, head of the investment research division at Akatsuki Securities Inc.

Possible negative headlines about the new pneumonia may steal market attention from upcoming earnings releases from major Japanese companies, Fujii said, adding that investors will be more cautious about earnings forecasts by exporters.

Falling issues far outnumbered rising ones 1,961 to 166 in the first section, while 32 issues were unchanged.

Volume increased to 1.180 billion shares from 965 million Friday.

Stocks that had been expected to enjoy demand from visitors from China during the Lunar New Year holiday period met with selling, after the Chinese government banned overseas travel by Chinese nationals starting Monday. Major losers included airlines JAL and ANA, department store operators Takashimaya and Isetan Mitsukoshi, and cosmetics makers Shiseido and Kose.

Semiconductor-related issues such as Advantest and Tokyo Electron suffered a sharp sell-off due to concerns over a slowdown in the Chinese economy due to the new pneumonia.

Oil names including JXTG and Cosmo Energy lost ground, hit by falling crude oil prices.

Among other major losers were clothing store chain Fast Retailing and industrial robot producer Fanuc.

By contrast, a handful of winners included realtors such as Mitsui Fudosan and Mitsubishi Estate.