TOKYO -- SoftBank Group CEO Masayoshi Son said Thursday he will donate 1 million masks to elder-care facilities and doctors, after backtracking on his original plan to offer free testing kits.

"I completed an order to procure [the masks]," Son said in a Twitter post Thursday night that was quickly retweeted thousands of times.

Son emerged on Twitter this week for the first time in three years to declare his support in battling the pandemic, drawing the interest of investors and the public. The tweets came as SoftBank's shares tumbled amid a sell-off in global financial markets. The Japanese company fell 6.3% on Thursday to its lowest level since January 2019.

The Twitter muddle began Tuesday night, when Son suddenly posted from his personal account that he was "worried about the new coronavirus situation."

On Wednesday, Son followed up with a plan: provide free testing kits to 1 million people. Sending kits to people's homes will allow them to test for the virus and prevent them from spreading the illness by visiting medical institutions, Son argued, adding that a similar approach is being taken by fellow billionaire Bill Gates.

But the plan triggered an uproar among social media users, some of whom said the kits would cause chaos among testing facilities. Others voiced support for the effort. But within hours, Son tweeted again that he may scrap the plan because it had a "bad response."

Son was active on Twitter after the powerful earthquake and tsunami that caused the Fukushima nuclear disaster in 2011, voicing his concern over the safety of nuclear power plants. But tweets became less frequent as he began transforming SoftBank into a tech investment powerhouse through the launch of its nearly $100 billion Vision Fund about three years ago.

Son, who has told Vision Fund-backed companies to focus on a path to profit after suffering a huge loss on its investment in WeWork, is likely feeling fresh pressure from the unfolding economic damage caused by the new coronavirus.

Chinese media reported Wednesday that Oyo, the SoftBank-backed Indian hotel startup, is cutting thousands of employees in China and that some of its top local executives have left. Asia makes up 48% of the Vision Fund's portfolio, according to the company.

"SoftBank is an investment company. Its share price reflects the decline in the value of its assets," said Shinji Moriyuki, an analyst at SBI Securities.

Yet a successful response to the coronavirus outbreak may boost Son's reputation. Health care technology has become a focus for SoftBank's investment strategy, partly because some of the Vision Fund's best-performing investments, like U.S. startup Guardant Health, are in that sector.

SoftBank recently participated in a $165 million funding round for Karius, a U.S. startup that uses blood samples to detect infectious diseases.