British authorities evacuated buildings and deployed military bomb disposal teams over a "major incident" in the town of Whelford on Sunday morning.

London's Metropolitan police said five men were arrested on suspicion of preparing a "terrorist act" and explosive-related offenses.

The town is located near the Fairford air base, which is used by the US military. Around 30 emergency vehicles were seen in the area, including police cars, ambulances, and fire engines. The authorities said they believed the incident to be "contained."

Counter-terrorism police were leading the probe.

"We are in the early stages of an investigation," Deputy Assistant Commissioner Vicki Evans said in an online statement, adding that the authorities were "working closely with our partners" to understand the circumstances of the incident.

The statement urged the public to share any information they may have related to the issue.

Bomb disposal units examining three 'suspicious vehicles'

Local police said they had received a call overnight on Sunday about "three suspicious vehicles" heading to the base.

"Armed officers responded and subsequently arrested five men in the Whelford area," assistant chief constable Richard Ocone told reporters.

He added that a cordon of 400 meters, or approximately 1/4 of a mile, has been put in place around the vehicles "while the army's explosive ordinance disposal unit examine them."

"As a precaution, around 85 households have been advised to evacuate while these examinations take place," Ocone said.

He added that some of the evacuees were taken to a nearby leisure center.

The Gloucestershire police representative also asked the public "not to speculate" but follow official channels instead.

Officials stay tight-lipped

A spokesperson for ​the US Air Force refused to discuss specific steps when contacted by the Reuters news agency, saying only that both US and British forces "remain vigilant and will take ⁠appropriate ​actions to ensure the safety and security of our ​US service members, civilians, contractors, and their families."

The background for the incident was not immediately clear.

The UK has allowed the US to use Fairford for its war against Iran, with Iran's Revolutionary Guards warning UK officials against the move this summer. The evacuations also come at a time of heightened tensions in Northern Ireland, and less than two months after Germany discovered an explosive-laden drone at the Leipzig airport, which its authorities attributed to Russia.

Edited by: Sean Sinico and Wesley Dockery 

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