An explosion occurred near Fairford Air Force Base in the UK, five people were arrested and a counter-terrorism investigation was launched.

British police have launched a counter-terrorism investigation after an explosive-related incident occurred near a British air force base used by U.S. bombers for air strikes against Iran.

According to the Associated Press and BBC, Gloucestershire police received a report at around 0:45 a.m. on the 27th (local time) that three 'suspicious' vehicles were moving toward Fairford Air Force Base.

Police classified this as a 'serious incident'. A 400m radius around the vehicle was completely controlled, and residents of 85 nearby households were urgently evacuated.

Counter-terrorism police are leading the investigation, and five people arrested on suspicion of violating the Explosives Act are being investigated for additional charges of preparing for terrorism.

An aerial video from a local broadcast showed an explosive disposal robot being deployed between three controlled white vans.

The police have not yet officially confirmed the specific connection between this incident and the military base.

Fairford Base is home to the U.S. Air Force's 501st Combat Support Group and the 420th Air Base Squadron. This base has been used as a launch base for limited airstrikes targeting Iran.

A U.S. Air Force spokesman told The Associated Press that U.S. and British authorities remain vigilant and will take appropriate measures to ensure base safety, adding, "For operational security reasons, we will not discuss specific protective measures."

The British Prime Minister's Office said that Prime Minister Andy Burnham is continuously being briefed on the situation regarding this incident.

This incident came amid growing concerns that Iran was mobilizing proxy forces to plot terrorism and other crimes on British soil.