Two of the U.S. Air Force's newest and most advanced jets landed in the Baltic state of Estonia for the first time on Tuesday, a symbolic gesture meant to reinforce the United States' commitment to the defense of NATO allies that border Russia.The visit of the F-35 stealth fighters, which flew from Britain and spent several hours in Estonia, is part of a broader U.S. jet pilot training across Europe as the NATO alliance seeks to deter Moscow from any possible incursion in the Baltics.In response to NATO's recent deployment, Chief of Russia's General Staff Army General Valery Gerasimov stated that it would "disrupt a balance of forces in the region and increase the risks of military incidents," as reported by Russian news agency TASS."The current differences, first and foremost, between Russia and NATO, continue to grow. The alliance has been expanding, continuing large-scale military activities on its 'eastern flank,'" Gersimov said at the 6th Moscow conference on international security. "Russia will have to take appropriate retaliatory steps and the necessary measures of restraint," he added.The deployment of NATO troops and equipment, as well as strong words of support from senior U.S. officials, have helped to reassure Baltic leaders who had been worried about U.S. President Donald Trump's commitment to defending Europe.The F-35 deployed to Europe are permanently stationed at a U.S. air base in Utah and are part of the Pentagon's most expensive weapons program, estimated to cost around $400 billion. One of the U.S. Air Force pilots of the F-35 planes was Lt. Col. George Watkins, who was impressed with the aircraft's performance."The F-35s are amazing," said Watkins, who has flown the plane for around two years now. "It takes our capability to a whole new level of technology. Just the stealth capability alone is really amazing for the pilot because it increases our survivability and allows us to go where other planes can't go."He said the plane conducted one airborne refueling session from the accompanying KC-35 tanker plane during the three-hour flight en route from Lakenheath in eastern England to the Baltic country.Earlier this month, the U.S. Air Force deployed a fleet of F-35s, its newest and most powerful fighters, to Britain to reassure U.S. allies in the face of Russian aggression. U.S.A.F. said the F-35s will remain "a period of time" in Estonia to conduct air drills with NATO aircraft in the region "in a realistic training environment."F-35s are in use by the U.S. Air Force, Marine Corps and Navy, and by six other countries: Australia, Britain, Norway, Italy, the Netherlands and Israel. Japan took delivery of its first jet in December. Estonia and its Baltic neighbors Lithuania and Latvia are former parts of the Soviet Union and today are members of NATO. They requested greater NATO support following Moscow's annexation of Ukraine's Crimea peninsula in 2014 and its support for separatists in eastern Ukraine.