A British retired couple who were on a yacht which had warning shots fired near it by a Russian warship in the English Channel have described the "surreal" experience to BBC Newsnight.

Jane and Alan Kelvey were sailing 23 miles off the coast of the Isle of Wight on Tuesday morning when they came into close contact with a Russian frigate, the Admiral Grigorovich.

The warship fired into the UK-registered yacht's path, in what the Ministry of Defence has described as an "isolated incident".

Russia's Defence Ministry said the yacht had been on a "dangerous approach" towards the warship, but the couple said they were "definitely not on a collision course".

Recounting the incident, Jane Kelvey told BBC Newsnight: "[The warship] gave out five blasts on their horn, which means 'have you seen us?'

"We immediately turned two degrees to port so they could see we had made a deliberate change of course, which meant we had seen them.

"Then a minute or so later they gave another five blasts on their horn, immediately followed by four to five small arms fire.

"That wasn't aimed at us – it was warning fire that went up in the air, we believe."

In a statement earlier on Tuesday, the Russian Defence Ministry said the yacht had been on a "dangerous approach" towards the warship.

It said the Admiral Grigorovich's crew had fired into the yacht's path with rifles after making several attempts to contact it over the radio and after launching warning flares.

The ministry said its sailors had acted in "strict accordance with international shipping regulations".

A Ministry of Defence (MoD) spokesperson told the BBC: "Following attempts to contact a British vessel in the channel, the Grigorovich fired warning shots. These were not aimed at the vessel and were an attempt to prevent a possible collision."

Jane said their yacht, the Bright Future, was "definitely not on a collision course".

"As far as we were concerned, it wasn't an incident until the gunfire started," she said.

She called the gunfire "completely unnecessary", and said she reported the incident as a hazard to navigation "because that's what you're supposed to do".

The incident happened around 20 nautical miles – around 23 standard miles – south of the Isle of Wight, outside of UK territorial waters.

British authorities said they received reports from the yacht's occupants on Tuesday morning that a Russian vessel had fired warning shots from around 500 yards (457m) away – a relatively near distance by the standards of sea travel.

The BBC understands that the small, motor-less yacht had drifted towards the warship in foggy conditions after setting off from the UK.

British officials believe the Admiral Grigorovich was attempting to signal it was drifting rather than being powered by its engines, therefore making it less manoeuvrable – possibly leading its crew to assess it was more vulnerable to a collision.

A boat from HMS Tyne, a British patrol vessel, was sent to the yacht to gather details and check on the safety of the crew.

When BBC Newsnight's Victoria Derbyshire asked the couple if they were afraid after hearing gunfire, they calmly told her they were not.

Jane chuckled and joked that she just crouched down and put her canvas hood over her head "to protect her" while her husband continued to steer.

Speaking after the interview, Derbyshire said they seemed both bemused and mildly irritated by the Russian Defence Ministry's statement that they had been on a "dangerous collision course".

The incident comes days after Royal Marine Commandos intercepted a Russian shadow fleet tanker carrying sanctioned oil in the Channel on Sunday, in the first operation of its kind carried out by the British military.

The MoD said the firing of warning shots on Tuesday was an "isolated incident" and not linked to Sunday's tanker seizure.

Russian warships regularly pass through the Channel in international waters and are routinely monitored by Royal Navy vessels.

The Admiral Grigorovich was being shadowed by the HMS Mersey, as it had been for several days after being spotted off the coast of Brest in France, in what the Royal Navy described as a "routine operation".

Last week, a Nato source told BBC Verify that the Admiral Grigorovich had been ordered by Moscow to escort shadow fleet vessels through the Channel.

The frigate is understood to have been operating in the area for some time and had been repeatedly re-supplied by a repair vessel.

Satellite images reviewed by BBC Verify have shown the repair vessel, the PM-82, operating between the Channel and the North Sea in recent months.

Nato officials believe the PM-82 delivered food, water and other supplies to the Admiral Grigorovich, allowing it to stay at sea for extended periods of time and lead Russian convoys through the Channel.

In April, the frigate was reported to have escorted six shadow fleet vessels through the waterway while being monitored by the Royal Navy.

The Royal Navy previously said the Grigorovich escorted Russian-flagged vessels heading to and from the Atlantic, Mediterranean and Baltic, including "one submarine and around six merchant and support vessels".

James Parkin, a former Royal Navy rear admiral, says the use of armed force is a last resort, reserved only for self-defence.

"I would not be surprised if it was a miscalculation, rather than a deliberate act to try and fire on a British yacht very close to British waters," he told BBC News.

While the MoD has assessed Tuesday's incident was not linked to the seizure of the Russian shadow fleet tanker at the weekend, Parkin said that had been a "huge embarrassment" for Moscow, given there "is a Russian navy ship in the English Channel who is only there to stop this kind of thing happening".

Coming at a time of heightened tension between the UK and Russia, and on the day when two departing UK defence ministers, in their resignation speeches, sounded the alarm about Russia's increasingly aggressive behaviour, this relatively minor incident has, perhaps inevitably, been magnified.

Additional reporting by BBC Verify's Matt Murphy and Tabby Wilson.