Four American B-52 long-range bombers landed at RAF Fairford in Gloucestershire on Thursday after ground crew and logistics personnel were reported to have arrived two days earlier.
The deployment comes amid heightened tensions between the West and Russia, but officials claimed the Bomber Task Force mission – a joint practice operation – had been planned for a long time.
The nuclear-capable bombers, which have been in US military service since 1955, took off from their home base of US Air Force Minot in North Dakota before refueling in Nova Scotia.
A number of aircraft enthusiasts caught the moment the mammoth planes landed.
Flight tracking data suggested two of the aircraft engaged in various activities over the UK before landing.
“En route to RAF Fairford, US Bomber Aircraft integrated with British Typhoon aircraft and Portuguese F-16s currently assigned to NATO’s Icelandic Air Policing mission,” a statement from the US Air Force, published by Gloucestershire Live, read. It added that the bomber aircraft also “integrated with British Joint Terminal Attack Controllers (JTAC) to conduct bilateral Close Air Support training.”
The deployment comes after UK Prime Minister Boris Johnson said the Ukraine crisis was reaching “the most dangerous moment” in coming days, with Britain vowing to back Kiev against alleged Russian aggression. Moscow has repeatedly denied any intention to invade Ukraine.
The US is deploying a total of 3,000 troops to forward bases in Europe to reinforce NATO positions.
The US already has a considerable deployment in the UK, including a sizable air force contingent including the 100th Air Refueling Wing, 352d Special Operations Wing and 501st Combat Support Wing at RAF Mildenhall.