In its annual report on military spending, the International Institute for Strategic Studies said the United States stayed firm as the top military spender in the world last year, with defense spending in excess of US$600 billion.
China came second with $112 billion, followed by Russia and Saudi Arabia. Korea ranked 11th, at $32 billion.
Global defense spending has been on the decline ever since 2009, according to the report.
Nearly 60 percent of European countries have cut down their military budgets, with an overall decrease of 2.5 percent, but Middle Eastern nations have gone in the opposite direction.
Saudi Arabia and Oman's military spending have grown by more than 30 percent over the past two years, which was attributed to the recent unrest in the region.
China, Japan and Korea accounted for more than half of the spending in Asia, which has increased by roughly 12 percent in three years.