HONG KONG — China is investing in Silicon Valley start-ups with military applications at such a rapid rate that the United States government needs tougher controls to stem the transfer of some of America’s most promising technologies, a Pentagon report says.

There are few restrictions on investing in American start-ups that focus on artificial intelligence, self-driving vehicles and robotics, the report contends, and China has taken advantage. Beijing, the report says, is encouraging its companies to invest for the purpose of pushing the country ahead in its strategic competition with the United States.

In some instances, Chinese companies have made under-the-radar investments intended to dodge the oversight of a government agency, the Committee on Foreign Investment in the United States, known as Cfius.

“If we allow China access to these same technologies concurrently, then not only may we lose our technological superiority, but we may even be facilitating China’s technological superiority,” the report says.