(Express) Ciaran McGrath May 2 2019 17:56 CHINA will keep pushing the envelope" particularly in the South China Sea region as it prepares to unveil its first stealth fighter before the end of the year and is also developing long-range bombers capable of carrying nuclear weapons a top US Air Force commander has warned. And General Charles Brown the head of Pacific Air Forces admitted the region would see a military escalation in the years to come as the US seeks to keep pace with the emerging superpower. Mr. Brown said the J-20 fighter could possibly" be operational this year indicating greater threat greater capability" for China in the Pacific. The US would seek to counter Beijings build-up with increased deployment of next-generation F-35 jets and continuing overflights of strategic areas such as the South China Sea he acknowledged. He told Bloomberg: My sense of the way the Chinese operate is somewhat incremental. Theyll continue to push the envelop to figure out does anybody say or do anything - if you dont push back itll keep coming." China already has the worlds third largest air force with more than 2500 total aircraft including 1700 combat fighters strategic bombers tactical bombers and multi-mission tactical and attack aircraft the US Defense Intelligence Agency said in a report earlier this year. Chinas J-20 fighter is part of a modernization effort thats been closing the gap with Western air forces across a broad spectrum of capabilities such as aircraft performance command and control and electronic warfare" the report said.