Earlier this month, The Chinese People’s Liberation Army Air Force declared its Chengdu J-20 fifth-generation stealth fighter operational. The aircraft has been in development for years and it is a sign of Beijing's ambition to challenge U.S. technological superiority and its F-22 and F-35 aircraft in particular.
Russia has also been overhauling and upgrading its old Cold War-era equipment. It has unveiled new weapons systems such as its own stealth fighter, the Sukhoi Su-57 PAK-FA as well as the T-14 Armata tank.
The shifting trends in military expenditure can be seen on this infographic which uses Sipri data. While military spending has declined in the UK and the U.S. since 2007, China and Russia have recorded spending increases of 118 and 87 percent respectively in that time period.