Two pilots of a Royal Navy jet have been taken to hospital, after they ejected from their Hawk T1 near Helston, Cornwall.
The pair, from 736 Naval Air Squadron, had been flying from RNAS Culdrose.
They were airlifted to Derriford Hospital in Plymouth, but Cornwall Air Ambulance said their injuries were "not life-threatening".
Devon and Cornwall Police said emergency services remain at the scene of the incident in a farmer's field in St Martin near Culdrose.
The Ministry of Defence said "an investigation will begin in due course".
Eyewitness Layla Astley said she heard a "loud crack" and "two pilots ejecting".
Two pilots are being checked by medics after ejecting from a Royal Navy Hawk aircraft from 736 Naval Air Squadron during a flight from RNAS Culdrose.— Ministry of Defence Press Office (@DefenceHQPress) March 25, 2021
An investigation will begin in due course. We won't be providing further detail at this time.
She wrote on Twitter: "I saw the plane flying low over our house, I heard a clunking sound, it flew on over our fields and then there was a loud crack and we saw two pilots ejecting, I watched as their parachutes opened.
"I then saw the plane bank left and over the top of a hill before hearing a very loud bang.
"There was no smoke or fire and I hear from locals that thankfully no one was seriously hurt."
Cornwall Air Ambulance tweeted: "Critical care paramedics assessed and treated two patients who had ejected from the aircraft. Injuries were not life-threatening."
An HM Coastguard helicopter was also at the scene.
WATCH: Aviation expert says the Hawk has an '"excellent safety record".
Why does 736 Naval Air Squadron fly the Hawk?
According to the Royal Navy's website, the Hawk Mk1 twin-seat fast jet is primarily used for training purposes.
They are used to provide simulated ship attack and airborne intercept training for ships in the Royal Navy fleet.
The jet has a top speed of more than 1,000kmph and a range of more than 2,250km.
The Defence Command Paper confirmed the Hawk T1 is among the British aircraft set to be retired in the coming years.
736 Naval Air Squadron is the Navy's "maritime aggressor squadron" and its pilots are used to provide "airborne threat simulations that allow for realistic training at sea", the Navy's website states.
Equipped with the Hawk T1, the squadron's primary role is to supply simulated ship attacks for Navy and NATO units in the build-up to deployments.
Pilots use the jets to replicate the threats from enemy fighter aircraft and high-speed sea-skimming missiles.
The Navy website adds that 736 Naval Air Squadron also fly missions for students at the Royal Navy School of Fighter Control.