NEW YORK (BLOOMBERG) - China may declare its first stealth fighter operational this year, as it also develops long-range bombers capable of carrying nuclear weapons, part of a regional build-up by Beijing that the United States is closely monitoring, according to the US Air Force's Pacific commander.

General Charles Brown, the head of Pacific Air Forces, said the stealthy J-20 fighter could "possibly" be operational this year, a move he said would signal "greater threat, greater capability" for China in the Pacific.

He went on to emphasise that US efforts to counter those developments include rising deployments of next-generation F-35 jets and continuing overflights of strategic areas such as the South China Sea.

"My sense of the way the Chinese operate is somewhat incremental," Gen Brown said in an interview this week at Bloomberg's headquarters in New York.

"They'll continue to push the envelop to figure out does anybody say or do anything - if you don't push back it'll keep coming."

Fielding the J-20 would add to what is already the region's largest air force and world's third largest, with more than 2,500 total aircraft including 1,700 combat fighters, strategic bombers, tactical bombers and multi-mission tactical and attack aircraft, the US Defence Intelligence Agency said in a report earlier this year.

China's J-20 fighter is part of a modernisation effort that's been "closing the gap with Western air forces across a broad spectrum of capabilities, such as aircraft performance, command and control and electronic warfare", according to the report.

Gen Brown also said he thinks China is moving to develop dual-use bombers that would be "similar to our bombers" in terms of being able to carry nuclear weapons and non-nuclear precision-guided weapons.

"I don't think it would be too far off the mark to say they could do that as well," Gen Brown added, without indicating whether China may have a stealth bomber capability.

Acting Defence Secretary Patrick Shanahan, in a statement on Wednesday for the House Defence Appropriations subcommittee, said a Chinese long-range bomber "if successful, would make it only one of three nations (to) possess a nuclear triad" of land, sea and air-based nuclear capabilities.

COMBAT EXPERIENCE

The US has a number of ways to counter China's build-up, Gen Brown said. That includes being unpredictable in deployments of the B-1B, B-52 and B-2 bombers.

The B-1B, Gen Brown said, is now qualified to carry a new Lockheed Martin Corp anti-ship missile, a few of which have been stockpiled in the Pacific region.

Gen Brown, a four-star general who has logged more than 130 combat flight hours out of 2,900 overall, was on the US East Coast this week to speak with Asia experts about the challenges facing his command.

He started in the job more than eight months ago after serving as deputy commander of US operations in the Middle East and head of the air war against Islamic State in Iraq and Syria (ISIS) in 2015-2016.

A key issue for Gen Brown in his latest post is "how do I gain a greater understanding of how China operates - not only their equipment capability - but how they operate, how they command and control. I want to understand what makes their blood pressure go up" so as to avoid miscalculations.

"Their propensity to fly out over the water has increased over the years," he said.

TAIWAN'S F-16s

It is not just the US noticing the increased Chinese capability, Gen Brown said.

He touched briefly on the State Department and Pentagon's review of a potential sale of new F-16s to Taiwan.

US President Donald Trump's advisers encouraged Taiwan to submit a formal request for the jets. That request would need to be converted into a formal proposal by the Defence and State Departments, and then Congress would have 30 days to decide whether to block the sale.

"There's been a little increase in tension there recently, which may be the impetus" behind Taiwan's request, Gen Brown said.

The Beijing government considers Taiwan's fate a "core interest" - more important than almost any other issue, and has increased pressure on countries and multinational companies to avoid actions that could imply sovereign status for the island.

The US, wary of antagonising China, hasn't sold advanced fighter jets to Taiwan since then President George H. W. Bush announced the sale of 150 F-16s in 1992.

The Obama administration rejected a similar Taiwanese request for new jets, agreeing in 2011 to upgrade the island's existing fleet.