The suspects were released on bail about 38 hours after they were detained near the perimeter of the Royal Air Force base, which is used by American aircraft to strike Iran. Police arrested the five men before dawn on Sunday after residents reported seeing men in black balaclavas running toward the secure area.
The move has ignited debate about the scale of the threat to the base and the surrounding community, following fears that the alleged perpetrators could have bombed the airfield. Amid suspicions that Iran was behind the plot, UK ministers and police officials have cautioned against speculating about the source of the threat. The Iranian government has declared it had no role in the incident.
Armed police have maintained road blocks and security checks around the base as the investigation continues.