The Wall Street Journal has the story:

Chinese officials acknowledged in a secret December meeting that Beijing was behind a widespread series of alarming cyberattacks on U.S. infrastructure, according to people familiar with the matter, underscoring how hostilities between the two superpowers are continuing to escalate.

The Chinese delegation linked years of intrusions into computer networks at U.S. ports, water utilities, airports and other targets, to increasing U.S. policy support for Taiwan, the people, who declined to be named, said.

The admission wasn’t explicit:

The Chinese official’s remarks at the December meeting were indirect and somewhat ambiguous, but most of the American delegation in the room interpreted it as a tacit admission and a warning to the U.S. about Taiwan, a former U.S. official familiar with the meeting said.

No surprise.