"When I think about China and Russia, our ability to stay ahead of them in areas like artificial intelligence, machine learning and a series of partnerships and being able to leverage the private sector – this is what we must continue to do," Nakasone said at a US House Armed Services Committee hearing, when asked about Washington’s preparedness for competition in cyber space in the future.
This is an area where the United States always has to improve its capabilities, he added.
"We have to make sure we are watching this very carefully," Nakasone said.
Nakasone warned of the two nations' alleged efforts to make cyber attacks more sophisticated and intensive.
"One of the things that we do see is a rise in both scope and sophistication of our adversaries, both in terms of their ability to conduct cyber intrusions and attacks and their ability to defend their data," he said.
Nakasone refrained from specifying how much Russia, China, Iran and North Korea spent on cyber security last year.