China continues efforts to modernize, diversify and expand its nuclear arsenal, with about 500 operational warheads today and more than 1,000 likely by 2030, the Pentagon said.

In an annual report to Congress on military and security developments in China, the Defense Department said it expects China to continue its expansion and modernization efforts through 2035 in service President Xi Jinping’s objective of achieving “world class” status for the country’s military by 2049.

China “probably will use its new fast breeder reactors and reprocessing facilities to produce plutonium for its nuclear weapons program, despite publicly maintaining these technologies are intended for peaceful purposes,” according to the report.

According to US estimates, China probably completed construction of three new solid-propellant silo fields — totaling at least 300 new intercontinental ballistic missile silos — in 2022, “and has loaded at least some” intercontinental ballistic missiles into the silos.

A senior Defense Department official, speaking to reporters Wednesday on condition of anonymity due to the sensitive subject, played down concerns that China has recently accelerated its nuclear buildup, saying that projections become less reliable and additional variables come into play as the years go on.

The US will continue to urge China to be more transparent about its nuclear capabilities, the Defense Department official said, suggesting that its prior resistance to transparency may have owed to the numerical advantage held by the US and Russia.

China Foreign Ministry spokeswoman Mao Ning said Friday at regular press briefing in Beijing that the report is “filled with prejudice and distorts facts.”

“China is committed to peaceful development,” she said. “We have a stable and unique nuclear policy that is highly predictable.”

--With assistance from Philip Glamann.

(Updates with remarks from China’s Foreign Ministry.)