"We are seriously focused at U.S. Space Command on our pacing challenge, which is the People's Republic of China," Gen. Whiting told reporters during a call from Japan on April 24.

"The People's Republic of China is moving at breathtaking speed in space, and they are rapidly developing a range of counter-space weapons to hold at risk our space capabilities," he added.

"They're also using space to make their terrestrial forces—their army, their navy, their marine corps, their air force—more precise, more lethal, and more far-ranging."

Gen. Whiting was on his first Indo-Pacific trip after becoming the head of U.S. Space Command in January, succeeding Army Gen. James Dickinson. During his trip, he met with top military leaders from South Korea and Japan, including Adm. Kim Myung-Soo, chairman of South Korea's Joint Chiefs of Staff, and Japanese Defense Minister Minoru Kihara.

One particular concern was the number of Chinese satellites in orbit, Gen. Whiting said.

"Over the last six years, they have tripled the number of intelligent surveillance and reconnaissance satellites on orbit, and they have used their space capabilities to improve the lethality, the precision, and the range of their terrestrial forces," he said.

"And so that obviously is a cause for concern and something that we are watching a very, very closely."

China's satellite fleet stood at 359 systems as of January, according to his prepared remarks for a hearing of the Senate Armed Service Committee in February. He also noted that Beijing is developing hypersonic glide vehicles along with other advanced space weaponry to "overcome U.S. traditional missile warning and ballistic missile defense systems."