China remains the main threat to the United States globally but of increasing concern is its closer cooperation with Russia, Iran and North Korea, said an annual US intelligence report released Tuesday.

China is willing to deepen cooperation with Russia in cyber security, counter-terrorism and combating cross-border crimes, China's police chief told the head of Russia's Federal Security Service (FSB) in Beijing on Friday.

China has the ability to hit the U.S. with conventional weapons; compromise U.S. infrastructure through cyber attacks; and target its assets in space, the Annual Threat Assessment by the intelligence community said,