China's central bank on Friday declared all transactions involving Bitcoin and other virtual currencies illegal, stepping up a campaign to block use of unofficial digital money. Chinese banks were banned from handling cryptocurrencies in 2013, but the government issued a reminder this year. That reflected official concern cryptocurrency mining and trading might still be going on or the state-run financial system might be indirectly exposed to risks. Read: Coinbase is here: A cryptocurrency exchange goes public Friday's notice complained Bitcoin, Ethereum and other digital currencies disrupt the financial system and are used in money-laundering and other crimes. "Virtual currency derivative transactions are all illegal financial activities and are strictly prohibited," the People's Bank of China said on its website. Read: US says cryptocurrency expert violated NKorea sanctions Promoters of cryptocurrencies say they allow anonymity and flexibility, but Chinese regulators worry they might weaken the ruling Communist Party's control over the financial system and say they might help to conceal criminal activity. The People's Bank of China is developing an electronic version of the country's yuan for cashless transactions that can be tracked and controlled by Beijing.

Shares were mixed in Asia on Thursday after benchmarks closed broadly lower on Wall Street in a third day of retreat. The price of Bitcoin and other cryptocurrencies declined further. Stocks rose in Tokyo and Sydney but fell in Hong Kong and Shanghai. Japan’s government reported that exports rose 38% in April from a year earlier while imports climbed nearly 13%, indicating a recovery in overseas demand even as the country weathers its worst bout of coronavirus outbreaks so far. Exports to the U.S. rose 45% while those to China jumped nearly 34% in a strong rebound after last year’s shocks from lockdowns and other precautions taken to curb the pandemic. Read:Asian stocks follow Wall St lower as inflation worries mount The Nikkei 225 regained lost ground, edging 0.2% higher to 28,067.53, while Sydney’s S&P/ASX 200 surged 0.9% to 6,993.90. In Hong Kong, the Hang Seng skidded 0.7% to 28,381.13 while Seoul’s Kospi declined 0.5% to 3,157.70. Shares rose in Singapore and Jakarta but fell in Taiwan. On Wednesday, the S&P 500 index dropped 0.3% to 4,115.68 after recovering from a 1.6% slide earlier in the day. The benchmark index is on track for its second weekly loss in a row. Bank stocks were among the biggest decliners. Goldman Sachs fell 1.7% and Wells Fargo lost 1.5%. Retailers and other companies that rely directly on consumer spending also pulled the market lower. Home Depot slid 0.7%, Gap fell 3% and L Brands dropped 3.1%. Energy sector stocks, the biggest gainers so far this year, bore the heaviest losses as the price of U.S. crude oil skidded 3.5%. The Dow Jones Industrial Average fell 0.5% to 33,896.04. The Nasdaq fared better than the rest of the market, shedding less than 0.1%, to 13,299.74. Smaller company stocks also lost ground. The Russell 2000 index lost 0.8%, to 2,193.64. Digital currencies fell sharply after China’s banking association issued a warning Wednesday over the risks associated with digital currencies. Bitcoin’s price was down 6.2% to $38,140, well below its all-time high of over $64,800 reached a month ago, according to the crypto news site Coindesk. It swung in a huge range of as low as $30,202 and as high as $43,621 over the course of the day. That the headline out of China rattled crypto investors suggests the market was already weak, said Willie Delwiche, investment strategist at All Star Charts. “If Bitcoin had been holding up better, a headline like that would be dismissed more readily, but it comes at a time when Bitcoin was already well off its highs,” he said. “It gave people who were looking for a reason to sell cover.” The Bitcoin skid comes after longtime Bitcoin advocate Tesla recently recently said it would no longer accept Bitcoin as payment for its cars, reversing its earlier position. The selling was so intense that the web site of Coinbase, an online brokerage for digital currencies, was temporarily down in the morning. Coinbase’s stock dropped 5.9%, ending about 34% below the peak it reached on April 16, just two days after its IPO. Investors continue to focus on whether rising inflation will be temporary or whether it will endure. Prices are rising for everything from gasoline to food as the economy recovers from its more than year-long malaise. The fear is that the Federal Reserve will have to dial back its extensive support if inflation persists. That includes record-low interest rates and the monthly purchase of $120 billion in bonds meant to goose the job market and economy. Read:Amazon’s profit more than triples as pandemic boom continues The minutes from the central bank’s April meeting of policymakers, which were released Wednesday afternoon, reaffirmed the view that the Fed’s decision to keep its benchmark interest rate ultra-low remains the best policy approach, though some officials cautioned that some factors pushing inflation higher may not be resolved quickly. Treasury yields mostly rose. The yield on the 10-year Treasury note slipped to 1.66% from 1.67% late Wednesday. In other trading, U.S. benchmark crude oil added 11 cents to $63.46 per barrel in electronic trading on the New York Mercantile Exchange. It dropped $2.50 on Wednesday to $63.35 per barrel. Brent crude, the international standard for pricing, rose 9 cents to $66.75 per barrel. The dollar fell to 109.14 Japanese yen from 109.23 yen on Wednesday. The euro rose to $1.2185 from $1.2174.

Electric car maker Tesla will stop accepting Bitcoin as a payment, CEO Elon Musk tweeted on Wednesday, citing environmental concerns. “We are concerned about rapid increasing use of fossil fuels for Bitcoin mining and transactions, especially coal, which has the worst emissions of any fuel,” Musk said on Twitter. He added that cryptocurrency is a “good idea on many levels” but its promise cannot come at a “great cost to the environment.” Read:Consumer Reports tricks Tesla to drive with no one at wheel Tesla, he added, won’t be selling any of the Bitcoin it owns. The price of bitcoin fell about 5% to $51,847 after Musk’s comments on Twitter. Tesla’s stock finished Wednesday down 4.4%. Tesla said in February that it had invested around $1.5 billion in Bitcoin and it planned to begin accepting the digital currency as payment “soon.” The fair market value of Tesla’s Bitcoin holdings as of March 31 was $2.48 billion, according to securities filings. Bitcoin relies on computers, which rely on electricity, to exist. The number of computers and the energy needed to power them is rising — the growing value of bitcoin is directly tied to the amount of energy it uses. Bitcoin miners unlock bitcoins by solving complex, unique puzzles. As the value of bitcoin goes up, the puzzles become increasingly more difficult, and it requires more computer power to solve them. Estimates on how much energy Bitcoin uses vary. Read: Scrutiny of Tesla crash a sign that regulation may be coming A 2019 study by researchers at the Technical University of Munich and the Massachusetts Institute of Technology concluded that, in late 2018, the entire bitcoin network was responsible for up to 22.9 million tons of CO2 per year — similar to a large Western city or an entire developing country like Sri Lanka. Total global emissions of the greenhouse gas from the burning of fossil fuels were about 37 billion tons last year.

The hackers targeted the accounts of 130 people, some of its most high-profile users and were able to reset the passwords of 45 of those accounts, said Twitter.