China will likely have a stockpile of 1,500 nuclear warheads by 2035 if it continues to build up its nuclear forces at its current rate.
This is stated in a Pentagon report published on Tuesday, Reuters reports.
The figure underscores U.S. concerns about China's plans to expand its nuclear arsenal, although forecasts do not suggest China is speeding up the pace of its warhead development.
"They have a rapid build-up that is too significant to keep secret," a senior US defense official said during a briefing on the Pentagon's annual report on China's military strength.
"It raises the question of whether they are moving away from a strategy that was based on what they called effective deterrence," he said.
The report, which mainly covers activities in 2021, says China currently has a nuclear arsenal of more than 400 warheads.
The Pentagon's projection for China's nuclear arsenal of 1,000 warheads by 2030 remained unchanged, the official said, adding that the 2035 projection was based on an unchanged pace of expansion.
China says its arsenal is dwarfed by that of the United States and Russia, and that it is open to dialogue, but only if Washington reduces its nuclear stockpile to China's.
According to the think tank Stockholm International Peace Research Institute (SIPRI), the United States has a stockpile of about 3,700 nuclear warheads, of which approximately 1,740 are deployed.
Chinese leader Xi Jinping made it clear at the Communist Party congress in October that China would strengthen its strategic deterrent, a term often used to describe nuclear weapons.
The report echoes concerns about Beijing's increasing pressure on Taiwan, an island China views as a breakaway province.