One of three Air Force Global Strike Command B-2 Spirit bombers returns to home base at Whiteman Air Force Base in Missouri on March 20, 2011 after striking targets in support of the international response enforcing a no-fly zone over Libya. Reuters

The U.S. Air Force has sent its most advanced bomber to Europe for the first time, amid the still-festering Ukraine crisis.

Two B-2 Spirit stealth bombers, the most sophisticated warplanes ever employed in combat by the U.S., will be based for a “short-term deployment” at Fairford, a Royal Air Force base in England 90 miles (150 km) west of London -- just three hours’ flight away from the Russian border.

The U.S. Air Force news release announcing the deployment, which began on Monday, makes no mention of the Ukraine crisis. However, Adm. Cecil Haney, commander of the U.S. Strategic Command, is quoted in it as saying that this training mission “demonstrates to our nation's leaders and our allies that we have the right mix of aircraft and expertise to respond to a variety of potential threats and situations."

It’s not hard to read in the statement an indirect message to Russian President Vladimir Putin that, even after the withdrawal of most U.S. forces from Europe after the end of the Cold War, Washington has the ability to send advanced military hardware to the continent in support of its NATO allies.

The stealth bombers have been employed in Europe before, when they attacked targets in Serbia during the 1999 NATO bombing of Yugoslavia, but they were operating at the time from their base in Missouri, in the continental U.S., on round-trip missions that averaged 30 hours in duration.

B-2s have been sent in the past to the U.S. base on the Pacific island of Guam. They have also operated during Operation Iraqi Freedom, according to the U.S. Air Force, from an undisclosed “forward operating location,” possibly the island of Diego Garcia in the Indian Ocean. They have also taken part in operation Enduring Freedom, bombing targets in Afghanistan.

The U.S. has 20 B-2As, made by Northrop Grumman Corporation (NYSE:NOC). With a crew of two, they have a range of about 6,000 miles or 10,000 kilometers without in-flight refueling and can carry up to 50,000 lbs (23 metric tons) of bombs and missiles, both conventional and nuclear. The stealth bombers rely on their unconventional, flying-wing tailless design and special coatings to appear largely invisible to radar, which makes them ideally suited to penetrating the airspace of countries with advanced air defenses. The entire fleet is based permanently at Whiteman Air Force Base in Missouri.

The “Spirit of Indiana,” a B-2 Spirit from Whiteman Air Force Base, Mo., taxis down the runway at RAF Fairford, England, June 8, 2014. U.S. Air Force photo by Staff Sgt. Nick Wilson