A possible Iranian connection is reportedly being examined as counter-terrorism officers investigate a suspected explosives plot close to RAF Fairford in Gloucestershire.

Several men were arrested in Whelford after a local resident raised the alarm over three unusual vans which had arrived in the village overnight.

Photographs from the operation show five men being detained, with some pictured on the ground as armed officers moved in.

An Army Explosive Ordnance Disposal team was subsequently deployed to examine vehicles close to RAF Fairford, while residents were evacuated and roads surrounding the area were sealed off.

Police have confirmed that several men were arrested on suspicion of offences under the Explosives Act and that bomb-disposal specialists were examining a number of vehicles. Counter-terrorism police are reported to have taken the lead in the investigation.

Alert resident reportedly raised alarm

The major security operation appears to have begun after a resident became suspicious about vehicles which had arrived in Whelford.

Local resident Julian Tudsbery told the BBC that three unusual vans had appeared in the village overnight and that another resident quickly reported them to police.

Earlier reporting said the suspicious activity was reported through a 999 call, leading to the police response and arrests.

A witness subsequently described seeing five men being detained outside the perimeter of RAF Fairford.

The source material supplied to UKNIP reports that viable incendiary devices and chemicals were discovered inside one of the vans, while an Army bomb-disposal robot was seen examining the three vehicles.

Possible Iran connection examined

The location of the suspected plot has inevitably become a significant part of the counter-terrorism investigation.

RAF Fairford has been used by US forces for operations connected with the conflict involving Iran and had previously been specifically referenced in warnings from Iran’s Revolutionary Guard.

Investigators are reportedly considering whether there could be a state-sponsored dimension to the suspected plot.

However, no Iranian connection has been established publicly, and police have not said that Iran, the Revolutionary Guard or any other foreign state directed those arrested.

Independent reporting available on Sunday also stresses that the confirmed facts surrounding the arrests do not themselves establish an Iranian connection.

Five men pictured being detained

Pictures from Whelford show five men being detained during the operation.

A resident said he saw officers line up five men before instructing them to sit down. The witness said the men were searched and had their shoes and socks removed before being taken away.

Previous reports have suggested the removal of their shirts could indicate officers were taking precautions against the possibility of concealed explosive devices.

There has, however, been no official confirmation that any suicide vest was discovered.

RAF Fairford on heightened alert

RAF Fairford has reportedly been placed on FPCON Delta, the highest US military force-protection condition, while RAF Lakenheath in Suffolk has reportedly moved to Charlie alert.

The US Air Force has declined to confirm individual security measures but said its UK-based wings remained vigilant and would take appropriate action to protect personnel, civilians, contractors and their families.

Police have said the incident is believed to be contained, although the counter-terrorism investigation remains