(CNN) A Russian military exercise triggered an unusual warning at a critical US military base in Germany on Saturday that ballistic missiles had been launched, according to multiple US defense officials.
The warning at Ramstein Air Base resulted in several minutes of uncertainty and alarm until an all-clear was sounded, according to the officials.
The initial assessment is that the missile warning may have been triggered when US intelligence satellites detected a launch. Highly classified US military satellites that track the infrared trail of ballistic missiles determined that a submerged Russian submarine had test fired four intercontinental missiles from its underwater location in the Sea of Okhotsk off eastern Russia on Saturday.
The alarm was sounded in Germany moments later. A statement by the US military in Europe Monday acknowledged the incident at Ramstein and in the surrounding areas where personnel received computerized notifications. A missile warning was also sounded on Ramstein via a loudspeaker system.
The US military "received an alert via a warning notification system of a real-world missile launch. The control center followed proper procedures and acted in a timely manner to provide rapid and accurate notifications to all required personnel," according to the statement.
"No US aircraft or pilots were scrambled. The missile launch was determined to be part of a regional training exercise and within minutes the control center again followed proper procedures and provided updated notifications. We consistently and routinely monitor for any threats to our forces and our allies," the statement from US Air Force Europe-Army Africa read.
The statement did not acknowledge the Russian missile launch but multiple defense officials have confirmed to CNN that it occurred. One official said the Russians had issued a "notice to airmen" covering a period of days, warning to stay out of the specific area because of military activity. That is a typical notification procedure.
US Strategic Command was able to quickly confirm the missiles posed no threat, so it is not clear why the warning was triggered, officials said. One official noted the incident is concerning because there is always a potential for miscalculation given tensions with Russia. But there was no indication of a threat this time the official emphasized.
After the incident, the US military at Ramstein issued a statement on its Facebook page to the military community in the area.
"Today, the Ramstein Air Base Command Post was notified via an alert notification system of a real-world missile launch in the European theater. The Command Post followed proper procedure and provided timely and accurate notifications to personnel in the Kaiserslautern Military Community. The missile launch was then assessed to be part of a training exercise and not a threat to the KMC area. The situation is all clear. We'd like to thank our Command Post members for their quick response to ensure our people stay informed so they can take the proper safety precautions," the statement said.
In 2018, human error was blamed for a false alarm that a missile was heading for Hawaii.
CORRECTION: An earlier version of this story incorrectly described the location of the Sea of Okhotsk. It's located off eastern Russia.