Two parachutists in the skies over England had a close brush with U.S. fighter jets that roared under them during a jump earlier this year, U.K. government aviation officials said.

The skydivers were in freefall, traveling at about 120 mph vertically, on April 17 when a pair of American F-15s flew directly under them at about 345 mph, according to the U.K. Airprox Board, the national air safety investigation body, in a report that recently surfaced.

The jumpers were carrying out the jump over Chatteris Airfield, about 90 miles north of London.

"Once the parachutists had seen the F15s there was very little they could do to avoid the situation, having no control over their speed or direction whilst in free-fall," the report found.

The F-15 pilots never saw the jumpers — but even if they did, there would have been no time avoid catastrophe.

"As they overflew the drop site, it was unlikely that the pilots would have been able to see the parachutists and take avoiding action, and in this case they were unaware that they had flown beneath them," according to the report.

U.K. Airprox didn't specifically determine how close this near-miss was but said there was "Go-Pro footage filmed from the helmet of one of the parachutists" that showed the jumpers "could clearly see the F15s passing beneath."

The F-15s were based out of Royal Air Force Lakenheath, which is host to the U.S. Air Force's 48th Fighter Wing.

Pilots had not been warned about skydivers in the area, the report said. The F-15s had been passed off between two sets of air traffic controllers that day.

"Completion of the handover" came "at a busy time," leading to the miscommunication, according to the report.

Still, the pilots should have known skydiving is a regular activity in that area and "they should have questioned" air traffic controllers or just avoided that air space, the board found.

The report said officials have learn that proactive measures have since been taken "to remind all the crews of the need to avoid Chatteris parachuting site."