South Korean military officials said the country will buy 40 Lockheed Martin F-35A fighter jets. The deal, which includes an option to buy 20 more of the stealth fighters, will be managed by the U.S. foreign military sales program, which makes government-to-government deals that do not require an open bidding process, Yonhap reported Saturday. Terms of the deal were not reported. The 20 additional jets, however, will be purchased with consideration for future specification requirements, which means Boeing Co. and the European Aeronautic Defense and Space Co. would have a chance to secure a contract, Yonhap said. Changes in specifications are expected, as the additional 20 jets are would not be deployed until 2023 and 2024, Yonhap said. The current deal includes jets that would play an integral part of South Korea's "Kill Chain" defense system, which combines detection of attacks with preemptive strike capabilities. "The F-35A will be used as a strategic weapon to gain a competitive edge and defeat the enemy in the early stage of war," Joint Chiefs of Staff spokesman Eom Hyo-sik said at a news briefing. "The South Korean military will also use the aircraft to effectively deal with provocations."