The head of the FBI said Tuesday that China is pushing its preferences in the US election as part of broad intelligence operations, whose economic impact he called unprecedented.

Christopher Wray, director of the Federal Bureau of Investigation, did not say whether China backed either President Donald Trump or his presumptive Democratic rival Joe Biden, both of whom have harshly criticized Beijing.

"China's malign foreign influence campaign targets our policies, our positions, 24/7, 365 days a year," Wray said at the Hudson Institute.

"So it's not an election-specific threat; it's really more of an all-year, all-the-time threat. But certainly that has implications for elections and they certainly have preferences that go along with that."

US intelligence concluded that Russia intervened in the 2016 election, in part by manipulating social media, in an effort to elect Trump.

The Republican has criticized the 2016 finding and his administration has shown irritation over intelligence briefings that Russia is similarly interfering this year.

Wray was answering questions after a speech focused mostly on China's alleged economic espionage, cases of which he said have soared by 1,300 percent over the past decade.

FBI Director Christopher Wray, seen here during a February 2020 congressional hearing, says that China has preferences in the US election
FBI Director Christopher Wray, seen here during a February 2020 congressional hearing, says that China has preferences in the US election AFP / Brendan Smialowski

"It's the people of the United States who are the victims of Chinese theft on a scale so massive that it represents one of the largest transfers of wealth in human history," Wray said.

"If you're an American adult, it is more likely than not that China has stolen your personal data," he said, pointing to the massive 2017 data breach at credit reporting agency Equifax.

Wray said that China accounted for nearly half of the 5,000 ongoing counter-intelligence cases being pursued by the FBI.

"We've now reached the point where the FBI is opening a new China-related counterintelligence case about every 10 hours," he said.

Wray also said that China works "relentlessly" to identify "middlemen" to pressure US governors and other officials who take actions it opposes -- notably traveling to Taiwan, which is claimed by Beijing.

The Trump administration has taken an increasingly hawkish tone on China, including blaming the communist power for not stopping the coronavirus pandemic -- on which the president's own record has been criticized.

Biden in turn has accused Trump of abandoning Hong Kong, where China has clamped down on expression, in his bid to secure a trade deal.