The US is 'accelerating tests' and development of its B-21 Raider, a stealth bomber that will be capable of delivering precision long-range strikes anywhere in the world.

The military placed an initial order of 100 aircraft, with experts expecting more B-21 Raiders to be commissioned soon afterwards.

America unveiled the new bomber just weeks after China's military revealed two new combat aircraft of its own and surrounded Taiwan in an unannounced exercise, that was the world's largest naval demonstration since the end of World War II. 

Experts warn that by 2027, China is expected to outnumber US forces in the areas west of the international dateline where American forces are deployed.

The People's Liberation Army (PLA) is also rapidly advancing, with American officials warning its pace of modernization is 'unprecedented and far outpacing' US efforts.

'The PLA is the largest and most modern that it has even been. That is risk. That is uncertainty,' 412th Test Wing commander Brig. Gen. Doug Wickert warned during a briefing earlier this month. 'We are the smallest and oldest that we have ever been.' 

Wickert, who leads one of the most important Air Force units, further argued the US 'cannot afford' to take a 'step backward', before unveiling the new B-21 Raider and issuing his stark warning to Beijing.

'Today is not the day to start World War III, because we have this,' he said, gesturing to a large projection of the bomber.

The Edwards Air Force Base is currently 'accelerating' tests of the B-21 bomber and 'delivering integrated capability to the warfighter', Wickert revealed.

'This is one of the many, many things that you are working on right here that will change [PLA] Chairman Xi Jinping's calculus about our readiness,' he said.

The PLA is preparing for conflict, according to US officials, who cited how the Chinese military in December was conducting mock aerial attacks on shipping in Taiwan's waters and formed a two-deep naval blockade to restrict sea and air approaches from the west.