The Pentagon accused China Friday of using cyber-espionage to improve its economy and expand its military.

In an annual report to Congress, the Department of Defense said, “Chinese actors are the world's most active and persistent perpetrators of economic espionage.” The report went on to say that Chinese spying would continue to pose a growing threat to U.S. economic security.

The Pentagon said the main focus of the People's Liberation Army remains preparing for the possibility of hostilities in the Taiwan Strait. That includes deterring the U.S. from intervening in the event of conflict with Taiwan, which Beijing considers a rogue province.

China has advertised its long-term military ambitions with shows of new hardware, including its first test of a stealth fighter jet early last year and the launch of its first aircraft carrier last August.