Just hours before Chinese President Xi Jinping touches down in Washington, Republican presidential candidate Marco Rubio called for the U.S. to expel known Chinese spies operating in the country and protect sensitive databases by disconnecting them from the internet. The Chinese president arrives Thursday afternoon for a state visit in the midst of controversies relating to Chinese intellectual property theft and U.S. government data breaches.

"Our relationship with China is not at a good place at this moment. They've breached U.S. government databases, they've continued cyberattacks… over the last twenty years we've witnessed the single largest transfer of wealth in the history of the world a Chinese companies backed by the Chinese government have stolen proprietary data and U.S. state secrets," Rubio said at a Senate Intelligence Committee hearing with NSA Director Michael Rogers.

Rubio said the United States needed to "deter adversaries like China who will continue to attack us" by clearly stating how America will respond when it is attacked in the cyber domain. But as for Rubio's suggestion that the United States disconnect sensitive databases from the internet, Rogers was lukewarm. "There is a requirement in many instances to ensure information flow for the internet in the system, so the idea that you're going to be able to do some of these things with no internet depends on the situation... it can be problematic," Rogers said.

—Tim Mak