Beijing has said it has begun introducing its J-20 stealth fighter jets into combat units. The move boosts China’s ability to carry out the mission of defending its sovereignty, security and territorial integrity, Air Force spokesman Shen Jinke said Friday. The J-20 was first flown in 2011, and is seen as China’s answer to fifth-generation jets such as the US F-22 and F-35, AP said. The formal debut of China’s stealth fighter was at a 2016 air show in the country’s south. Last year, it was featured in a military parade marking the 90th anniversary of the founding of the People’s Liberation Army.