The US Air Force said it has responded to "suspected unauthorised drone activity" over RAF Lakenheath in Suffolk this evening.
No personnel, aircraft or infrastructure were affected, a spokesperson for the US Air Force said.
It comes after unconfirmed reports that sirens were sounded at the base, which residents reported hearing from a nearby village.
The Ministry of Defence has been contacted for comment.
Earlier this week at least 12 US Air Force aircraft departed the nearby RAF Mildenhall base.
West Suffolk MP Nick Timothy said he had been in touch with authorities at the base, and was told "there is no threat to the public, and the incident is now resolved".
"Given the raised threat level, I continue to encourage everyone to report anything suspicious or out of the ordinary to the authorities," he added in a social media post.
RAF Lakenheath hosts the US Air Force's 48th Fighter Wing, or the Liberty Wing as it is also known, which has nearly 7,000 active-duty personnel, some of whom are stationed at the base.
The Liberty Wing is the largest US fighter operation in Europe, its website says, employing four combat ready fighter squadrons.
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