The Department of Justice has accused China of sponsoring hackers who are targeting labs developing Covid-19 vaccines.
US officials have charged two Chinese men who allegedly spied on American companies doing coronavirus research and got help from state agents for other thefts.
The indictment comes amid a US crackdown on Chinese cyber espionage.
The US, UK and Canada last week accused Russia of seeking to steal research related to Covid-19.
The accusations against former electrical engineering students Li Xiaoyu and Dong Jiazhi released on July 21 include charges of trade secret theft and wire fraud conspiracy.
Prosecutors said the two men spied on a Massachusetts biotech company in January which was known to be researching possible cures for Covid-19. They also hacked a Maryland company less than a week after it said it was researching Covid-19.
Officials called the Chinese men private hackers who occasionally received support from Chinese intelligence agents, including an officer from the Chinese Ministry of State Security (MSS).
Li Xiaoyu and Dong Jiazhi previously stole “hundreds of millions of dollars’ worth of trade secrets, intellectual property, and other valuable business information” beginning in 2009, prosecutors alleged.
The indictment unsealed in Washington state said Li Xiaoyu and Dong Jiazhi – who reside in China – recently “researched vulnerabilities in the networks of biotech and other firms publicly known for work on Covid-19 vaccines, treatments, and testing technology”.
Countries where companies were targeted include Australia, Belgium, Germany, Japan, Lithuania, the Netherlands, Spain, Sweden and the UK.
According to the indictment, the hackers were able to infiltrate a British artificial intelligence firm, a Spanish defense contractor, and a Australian solar energy company.
Prosecutors said the men at times acted in their own self-interest – including one occasion when they demanded a ransom from a company in exchange for not releasing its private information – but at other times “were stealing information of obvious interest” to the Chinese government.
According to the indictment, the hackers “worked with, were assisted by, and operated with the acquiescence of” the MSS.
Li Xiaoyu and Dong Jiazhi allegedly stole military data and provided the Chinese government with the passwords of a democracy activist in Hong Kong and a former Tiananmen Square protester.
At the summit in Buenos Aires on December 1, the G20 leaders agreed a joint declaration that notes divisions over trade but does not criticize protectionism.
Presidents Trump and Xi held a “highly successful meeting”, the White House said in a statement.
The White House says the US tariffs on Chinese goods will remain unchanged for 90 days, but warns: “If at the end of this period of time, the parties are unable to reach an agreement, the 10 percent tariffs will be raised to 25 percent.”
The US says China agreed to “purchase a not yet agreed upon, but very substantial, amount of agricultural, energy, industrial, and other products from the United States to reduce the trade imbalance between our two countries”.
According to the White House, both sides also pledged to “immediately begin negotiations on structural changes with respect to forced technology transfer, intellectual property protection, non-tariff barriers, cyber intrusions and cyber theft”.
President Trump said earlier this year he wanted to stop the “unfair transfers of American technology and intellectual property to China”.
According to the US, China has also signaled it will allow a tie-up between two major semiconductor manufacturers which Chinese regulators have been blocking.
The White House statement said China was “open to approving the previously unapproved Qualcomm-NXP deal”.
The US also says China agreed to designate Fentanyl as a controlled substance. The opioid – much of it thought to be made in China – is driving a huge rise in drug addiction in the US.
Both sides have imposed tariffs on billions of dollars’ worth of goods. The US has hit $250 billion of Chinese goods with tariffs since July, and China has retaliated by imposing duties on $110 billion of US products.
President Trump had also said that if talks in Argentina were unsuccessful, he would carry out a threat to hit the remaining $267 billion of annual Chinese exports to the US with tariffs of between 10 and 25%.