Chinese state media labelled the United States a "mincing rascal" and "high-level hooligan" on Wednesday in response to Washington charging five Chinese military officers with hacking US companies to steal trade secrets.
The indictment on Monday was the first criminal hacking charge the US has filed against specific foreign officials, and follows a rise in public criticism and private confrontation between the world's two biggest economies over cyber espionage.
As a first response, China suspended a Sino-US working group on cyber issues. In an editorial, the Global Times, an influential tabloid run by the People's Daily, the official newspaper of China's Communist Party, said this was the "right move, but we should take further actions."
"We should encourage organisations and individuals whose rights have been infringed to stand up and sue Washington," the newspaper said. "Regarding the issue of network security, the US is such a mincing rascal that we must stop developing any illusions about it."
The Chinese-language version of the Global Times called the United States a "high-level hooligan".
Washington's legal approach against China is "high-handed and hypocritical", the People's Daily said, citing media reports that the US National Security Administration (NSA) spied on Brazilian President Dilma Rousseff.
"Suspending the operations of a bilateral group on cyber affairs is a reasonable start, but more countermeasures should be prepared in case Washington obstinately sticks to the wrong track," state news agency Xinhua said in a commentary on Tuesday. "Otherwise, it should take full responsibility for the consequences of the farce that features itself as a robber playing cop."
China summoned the U.S. ambassador on Monday, hours after the indictment, warning Washington it could take further action, the foreign ministry said.
The cyber spying charges are likely to further sour ties between China and the United States, already under strain from a range of issues, including human rights, trade disputes and China's growing military assertiveness in contested seas.
On Wednesday, however, Du Yuejin, a top official in charge of internet security, was making a rare address to members of the American Chamber of Commerce in Beijing on "the current global deficit of trust on cybersecurity".
While China is unlikely to hand over the five officers charged, the indictment would prevent them from travelling to the U.S. or any country with an extradition agreement with the United States.