Bedfordshire Police responded to a suspicious incident in Slip End, near Caddington on Sunday, September 14.
Officers were called to the area on Sunday night, by a resident, after he saw two men acting suspiciously in a field.
As the area is under a Luton airport flight path, residents call the police if they see any suspicious activity.
They continued their search in the undergrowth on Monday.
A spokesperson for the police said: “Bedfordshire Police is responding to a report of a suspicious incident in Slip End on Sunday night.
“Further enquiries are on-going at this time and local officers are in the area to reassure residents.
“There is no intelligence to suggest anyone is in any danger at this time.
“Following our standard protocols when dealing with a suspicious incident in areas close to airports we can confirm that the Eastern Regional Counter Terrorism Intelligence Unit have also been assisting with this inquiry.”