The UK, US and Nato have offered reassurances that Russia will not get hold of the downed F-35B plane in the Mediterranean, insisting “we’ll get it first”.
The allies vowed to retrieve the £100 million ($133.7 million) warplane from the seabed after Britain said the Russians had been playing “close attention” to HMS Queen Elizabeth, which carried the jet before it went down.
Shortly after take-off last Wednesday, the plane ditched into the sea. The RAF pilot managed to safely eject.
"We'll get it first, I promise you," said Brig Gen Simon Doran, the top-ranking US officer on board the UK’s flagship aircraft carrier.
F-35Bs, fifth-generation warplanes equipped to carry out a range of different missions, differ from other F-35s and are designed for short take-off and vertical landing.
Fitted with radars, sensors and other classified technology, the jets are the most secret and complex aircraft in the UK arsenal. They also carry the highest price tag.
HMS Queen Elizabeth is returning from its maiden voyage to the Far East and is leading a nine-vessel allied strike group. It is currently near Sicily.
Nato's Deputy Supreme Allied Commander Europe, Gen Tim Radford, told journalists on board the vessel he had no worries about the possibility of a failed retrieval operation.
"We're not concerned at all about recovering it," he said. “We're not worried because we are working through the issue at the moment.
“There was obviously a concern when the plane went down. The pilot is safe, which is the most important thing.”
Gen Radford and other officials declined to give further details about the operation to salvage the jet.
Commodore Steve Moorhouse, commander of the carrier strike group, referred to the loss of the jet as “a hugely unfortunate incident” and “a setback”.
But he insisted “the reliability of the aircraft or confidence in it and the project is undiminished” after the loss.
The public pledge to find the jet came amid fears in Nato that Russia may try to recover the aircraft and glean the cutting-edge technology on board.
Last week Britain’s Defence Secretary Ben Wallace said Russia had been closely watching the movements of HMS Queen Elizabeth.
"It is not a secret the Russians have been very interested in the carrier group, both on the way out from the United Kingdom – as she's sailed and her group towards the Pacific – and now she is back in the Mediterranean," Mr Wallace told Sky News.
"Of course the Russians are playing close attention – it is what I'd expect.”
So far, the UK has accepted delivery of 21 American-made F-35Bs.
The majority of the planes are for its two modern aircraft carriers, HMS Queen Elizabeth and HMS Prince of Wales.