US submarine-hunting planes will operate from a Scottish airbase following a planned investment.
The US is spending 80 million dollars (£62 million) on development and refurbishment work at RAF Lossiemouth in Moray to meet their needs on site.
The new Lossiemouth facility is expected to be completed in 2020, to coincide with the initial operation of the UK’s new P-8A Poseidon maritime patrol aircraft.
The Ministry of Defence (MoD) has welcomed the planned contribution to the base from the US, which is set to cover a number of works at the air station.
These will include contributing towards refurbishment of the runway, additional aircraft parking and hangar space and accommodation to meet US requirements, it is understood.
The US has previously operated from RAF Lossiemouth but it is understood the improvements do not mean there will be a permanent US basing at the site.
Defence chiefs believe the RAF P8 fleet and the US submarine hunters will play a key role in keeping the UK and its allies safe.
An MoD spokeswoman said: “We are investing £3 billion in our nine-strong, new P-8A Poseidon fleet over the next decade.
“The contribution of 80 million dollars from the US to the home of our submarine-hunters at RAF Lossiemouth will support our partnership with our closest ally and will help us be more efficient by sharing improved facilities, and will see us patrol the seas together to have more eyes and ears on any aggressors.”
The MoD announced in April that RAF Lossiemouth was to be the future home of its new Poseidon fleet.
The aircraft’s key role will be to protect the UK’s submarine-deployed nuclear deterrent and its two new aircraft carriers, defence bosses said.