Officials in congressional testimony had earlier asserted that there had been a reduction in cyber thefts.
Commander of the US Cyber Command Admiral Michael S Rogers, in his testimony before the Senate Armed Services Committee yesterday said, "China has shown a worrying tendency to challenge the existing rules-based order, from which it has been a major beneficiary.
"It is pursuing its economic and diplomatic interests with greater assertiveness, rejecting, ignoring, or trying to rewrite norms that it perceives do not trend in its favour," he said.
Rogers said that China's behaviour in cyberspace exemplifies this trend.
For example, former US president Barack Obama and Chinese President Xi Jinping committed in 2015 that the two countries would not conduct or knowingly support cyber-enabled theft of intellectual property for commercial gain, he said.
"Subsequent evidence, however, suggests that hackers based in China sustained cyber espionage that exploited the business secrets and intellectual property of American businesses, universities, and defense industries," Rogers told the Committee.
The Justice Department just last fall unsealed indictments against three Chinese nationals, alleging they exfiltrated more than 400GB of data from several companies in the United States, he added.
"In addition, the Chinese government could exploit the production of information and technology products to harvest corporate, government, and even personal data from foreign countries," Rogers said.