More than 31 years ago, the relationship between the United States and the Soviet Union remained icy, and the Berlin Wall had yet to come down.

U.S. Air Force pilots were engaged in secret reconnaissance missions aboard the legendary SR-71 Blackbird spy plane. Many of those flights occurred over international waters in the Baltic Sea. These sorties were known as “Baltic Express” missions.

The SR-71 pilots would fly their aircraft at high altitudes while gathering imagery on key Russian bases — such as the Soviet Navy’s Northern Fleet on the Kola Peninsula — from international airspace.

During one such mission on June 29, 1987, a Blackbird flown by retired Lt. Cols. Duane Noll and Tom Veltri, experienced an engine failure.

The crew descended to roughly 25,000 feet over Swedish airspace where they were intercepted by two pairs of Swedish air force Saab 37 Viggen fighter jets. The Swedes were more than simply intercepting a wayward aircraft, they were offering defense from any opportunistic Soviets looking to harass an enemy spy plane on the fritz.

Given the tight corridor in the Baltic Sea, accidental airspace violations weren’t out of the realm of possibility. And Soviet fighter aircraft might have been looking for any reason, however slight, to enter into an air-to-air altercation.

This mission remained classified until last year. But with declassification has come official acknowledgement for services rendered.

On Nov. 28, in Stockholm, the U.S. Air Force finally presented four Swedish pilots with Air Medals for their actions back in 1987, according to a video of the ceremony posted by the Pentagon.

× Fear of missing out? Sign up for the Air Force Times Daily News Roundup to receive the top Air Force stories every afternoon. Thanks for signing up. By giving us your email, you are opting in to the Air Force Times Daily News Roundup.

"We were performing an ordinary peace time operation exercise,” recalled retired Maj. Roger Moller, one of the Swedish air force pilots. “Our fighter controller then asked me: ‘Are you able to make an interception and identification of a certain interest.’ I thought immediately it must be an SR-71, otherwise he would have mentioned it. But at that time I didn’t know it was the Blackbird.”

U.S. Air Force Maj. Gen. John Williams salutes the Swedish pilots who were awarded the U.S. Air Medal in Stockholm, Sweden, Nov. 28, 2018. Gen. Williams thanked the four Swedish airmen who risked their lives to save an SR-71 and the aircrew in 1987. (Senior Airman Kelly O'Connor/Air Force)

Once the Swedish pilots intercepted the damaged SR-71, they decided to render support to the aircraft by defending it from potential third-party aircraft that might have tried to threaten it, according to the Air Medal citation.

The pilots then accompanied the SR-71 beyond the territorial boundaries and ensured that it was safely recovered by American forces.

“I can’t say enough about these gentlemen,” said Veltri, one of the SR-71 pilots who was at the ceremony. “I am so amazingly grateful for what they did, but also for the opportunity to recognize them in the fashion we are doing. What these guys did is truly monumental.”

Noll, the other SR-71 pilot, was not able to be at the ceremony. However, he recorded a message which was played to those in attendance.

“Your obvious skills and judgement were definitely demonstrated on that fateful day many years ago. I want to thank you for your actions,” Noll said.

From left to right, Col. Lars-Erik Blad, Maj. Roger Moller, Maj. Krister Sjober, and retired U.S. Air Force Lt. Col. Tom Veltri stand beside the official photo which depicts the event that earned the Swedish pilots their U.S. Air Medals in Stockholm, Sweden. (Senior Airman Kelly O'Connor/Air Force)

“We will never know what would or could have happened, but because of you, there was no international incident," Noll added. "The U.S. Air Force did not lose an irreplaceable aircraft, and two crew members’ lives were saved. Lt. Col. Veltri and I can’t thank you sufficiently for what you prevented. Thank you for being highly skilled and dedicated patriotic fellow aviators.”

U.S. Air Force Maj. Gen. John Williams, U.S. Air Forces in Europe and Air Forces Africa mobilization assistant to the commander, presented the Air Medals to Swedish air force Col. Lars-Eric Blad, Maj. Roger Moller, Maj. Krister Sjoberg and Lt. Bo Ignell.

“That day in 1987 showed us that we can always count on our Swedish partners in times of great peril,” Williams said during the ceremony. “Even when there was both political risk and great physical risk in the form of actual danger, there was no hesitation on your part to preserve the pilots on that day.”

The presentation of Air Medals to the Swedish pilots represented a measure of gratitude from the U.S. military, as well as a longstanding partnership with Sweden between the countries, U.S. Air Force officials said.

The Swedish pilots also received a painting chronicling their heroics.