China's nuclear arsenal to more than triple by 2035: Pentagon

China's nuclear arsenal is likely to more than triple to 1,500 warheads by 2035, the Pentagon said in a Tuesday report that also highlighted the increasing sophistication of the country's air force.

Washington has identified Beijing as the most consequential challenge to the United States, and the annual report on China's military emphasized improvements to both its nuclear and conventional forces.

"The Department of Defense estimates that (China's) operational nuclear warheads stockpile has surpassed 400," the report said. "If China continues the pace of its nuclear expansion, it will likely field a stockpile of about 1,500 warheads" by 2035.

That figure would still however lag far behind the arsenals of the United States and Russia, which each include several thousand nuclear warheads.

China "probably intends to develop new nuclear warheads and delivery platforms that at least equal the effectiveness, reliability and/or survivability" of those under development by the United States and Russia, the report said.

Pentagon Press Secretary Brigadier General Pat Ryder said Tuesday that an increased Chinese nuclear arsenal would be a source of instability.

"The more proliferation there is, the more concerning it is, the more destabilizing to the region it is," Ryder told journalists.

The report also said Beijing is working to modernize its ballistic missile arsenal, launching some 135 in testing during 2021 -- "more than the rest of the world combined," excluding those fired in conflicts.

China is "developing new intercontinental ballistic missiles (ICBMs) that will significantly improve its nuclear-capable missile forces," the report said.

And Beijing's air force -- the third-largest in the world with more than 2,800 aircraft -- is making strides.

- 'New normal' -

It is "rapidly catching up to Western air forces and continues to modernize with the delivery of domestically built aircraft and a wide range of UAVs," according to the report.

"This trend is gradually eroding longstanding and significant US military technical advantages... in the air domain."

A senior US defense official, speaking before the report's release, said the Chinese air force is "trying to... progress rapidly on all fronts," including on the equipment it operates as well as its pilots and other personnel.

The report takes aim at the way in which China is employing its military in the Asia-Pacific region, saying it has "adopted more coercive and aggressive actions."

"Throughout 2021 and into 2022, (Chinese) vessels and aircraft have exhibited a sharp increase in unsafe and unprofessional behavior," risking "a major incident or accident," the report said -- an issue US Defense Secretary Lloyd Austin raised in a recent meeting with his Chinese counterpart Wei Fenghe.