Earlier, two of the RAF Lossiemouth-based aircraft had already spent three hours providing armed overwatch for British and American troops in Helmand province when the emergency call came in.
Officer Commanding 617 Squadron, Wing Commander Keith Taylor, said:
Whilst carrying out this task we received an urgent call to fly 300 nautical miles [556km] north west to an area near the Turkmenistan border to provide support to a joint United States and Afghan National Security Forces patrol that was coming under repeated small arms fire.
As the 617 Squadron aircraft were on-task for three hours prior to the call for assistance and had to refuel a number of times over the entire on-task period, this added to the length of the mission. Wing Commander Taylor said:
It was a marathon seven-hour, 45-minute flight [mission] and flying for that long requires a lot of fuel. We had to air-refuel four times and took on in excess of 20,000 litres of fuel each.
He said that after arriving one of the fighter bombers conducted a show of force to allow coalition forces to extract to safety.
The insurgents scattered to the cover of various buildings as the Tornado roared overhead at 100 feet [30m] and 500 knots [926km/h], allowing the patrol to withdraw.
The Tornado GR4s of 617 Squadron are operating as part of 904 Expeditionary Air Wing at Kandahar.
In the same week the squadron also conducted one show of presence, a higher-level flypast designed to indicate the presence of a Tornado, and four lower-level shows of force, all of which were successful in discouraging insurgents from attacking ground forces.