FAIRFORD, England — British police arrested five masked men a few hundred yards from RAF Fairford early Sunday morning on suspected explosives and terrorism charges, then released all five on bail the following day. The arrests, near a U.K. air base hosting U.S. forces that has hosted American and British warplanes for 80 years, have prompted visible anxiety in this small Cotswolds community and drawn statements from President Trump and investigators examining a possible Iranian connection.

The five men — all U.K. nationals living in London — were taken into custody after police received a tip from a local farmer who spotted the masked figures near the base. Residents of the nearby hamlet of Whelford were hastily evacuated by police and put up in area hotels. On Monday, authorities released the suspects on bail and said residents would be allowed to return home soon.

Mike Evemy, leader of the local district council, said there was “a degree of anxiety, especially those who were hurried out of their homes at dawn.” But other residents expressed skepticism about the severity of the alleged plot once the suspects were freed so quickly.

“Something doesn’t add up,” said Adrian Watkins, a local construction worker. “How serious can the incident have been if they let them go already?” Watkins suggested the men might have been after diesel fuel, which he said has been stolen with growing frequency amid high prices.

Jill Lavender, who has lived in the town for 50 years and was out walking her dog, said the incident seemed strange, “fairly amateur.” Like many in town, Lavender said the community liked having the Americans nearby and had never felt particularly threatened before by geopolitics — but added that many locals were less happy with the base’s recent use as a launchpad for attacks in the conflict with Iran, which Lavender described as unpopular and said had sent already high U.K. fuel and fertilizer prices even higher, hurting farmers.

President Trump said the men were “aiming to do big damage,” according to the Wall Street Journal. British security services said they were probing whether there was a link to Iran, which had previously warned the U.K. it could strike back for allowing the base to be used for attacks. The U.K. government initially turned down U.S. requests to use the site as a staging ground for attacks on Iran, angering the Trump administration, but later agreed to its use for strikes to protect U.K. allies in the Gulf from Iranian reprisals by hitting Iranian military sites.

Residents noticed increased security in recent weeks — more police patrolling the surrounding area, entrances to the base blocked by heavy equipment, and American servicemen who had not visited town in the past week. On Monday, no jets were taking off and no American servicemen were visible; the town was instead filled with visiting police and journalists.

A local farmer who tipped off police has said she does not understand why the men were allowed to get so close to the base, especially if U.S. and U.K. officials had evidence of a threat against the installation. Police cordoned off most of the area around the base following Sunday’s arrests.

Fairford has a symbiotic relationship with the base, which helps the local economy. The town is known for the original medieval stained glass windows in its ancient church and a world-beating air show held each year featuring the latest in military technology. Around town, lined with winding streets and tan-colored stone cottages, locals speak highly of the American servicemen and women, even if their commander in chief draws negative reviews from some. Bridget Kearney, who manages a pub frequented by the Americans, said: “We love having them here. They are so polite; I get tired of being called ‘ma’am.’” Another longtime local, Gordon Jones, said: “No one has a bad word to say about them.”

The base has been less popular with others, and was the site of protests in March and April from hundreds of antiwar activists.