Japanese F-15 fighters on Tuesday held drills with U.S. B1-B bombers, F-35 stealth aircraft and F-18 multirole combat jets above the East China Sea , south of the Korean peninsula, Japan 's Air Self Defence Force (ASDF) said.The exercise was the largest in a series aimed at pressuring North Korea following its ballistic missile tests. The latest launch, on Nov. 29, featured a new missile type the North said could hit targets in the United States, such as Washington D.C."The drill was meant to bolster joint operations and raise combat skills," the ASDF said in a statement.Two U.S. Air Force B-1B Lancer bombers flew from Andersen Air Force Base on the U.S. Pacific island territory of Guam, joined by six F-35s four F-18s and a tanker aircraft from U.S. bases in Japan.The Japanese air force dispatched four F-15 jet fighters and a patrol aircraft.