China's continued efforts to enhance its nuclear capabilities is a big worry, the U.S. said Friday.

Satellite photos show China is building more than 100 missile silos in a desert.

The U.S. demanded China to engage in talks to find "practical measures" to reduce the risk of a "destabilizing arms race." State Department representative Ned Price said China's buildup of nuclear capabilities deviates from its commitment to minimal deterrence.

"These reports and other developments suggest that the PRC's nuclear arsenal will grow more quickly, and to a higher level than perhaps previously anticipated," Price said.

Analysts studying the images said they identified the construction of at least 119 silos in a desert in Gansu province in the western part of China. The silos are believed to hold nuclear-capable intercontinental ballistic missiles.

The silos were first discovered by researchers at the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies. The satellite photos were provided by a private company called Planet.

 Price said the buildup was "concerning" and raised questions about China's intent. He said the U.S. and its allies should immediately pursue "measures to reduce nuclear risks."

During his speech at the centennial of the Communist Party, President Xi Jinping said any foreign country attempting to bully China would immediately "get their heads bashed." Xi pledged to strengthen the country's military. He also committed to the "complete reunification" of Taiwan.

Last year, the Pentagon estimated China had nuclear stocks in the "low 200s." The Pentagon projected China could potentially double its stocks as part of efforts to modernize its military. In comparison, the U.S. has around 3,800 nuclear warheads.

The U.S. has repeatedly called on China to join it and Russia in a nuclear arms agreement. China has ignored those calls saying its nuclear arsenal is "dwarfed" by those in the U.S. and Russia.