FBI counterintelligence division head E.W. “Bill” Priestap Wednesday said Chinese cyberespionage poses the “most severe” threat to American security at a Senate Judiciary Committee hearing on “Non-Traditional Espionage Against the United States.”

Priestap said China’s Communist Party “dominates every facet of Chinese life,” from religion to freedom of expression and business and that “it is therefore alarming that the Chinese government’s economic aggression, including its relentless theft of U.S. assets, is positioning China to supplant us as the world’s superpower.”

The hearing  comes as announcements of indictments of Chinese hackers and other actions planned for this week have been put off for now, officials said, declining to elaborate and as U.S. private sector and government investigators have begun pointing the finger at the China’s Ministry of State Security for the Marriott’s Starwood chain hotel reservation system breach.

Priestap added that China has used means that are clearly illegal such as hacking and commercial espionage and while some may appear legal but rely on deception, while others are not “are lawful but not reciprocal, exploiting the openness of free nations.”