First Minister John Swinney has warned that Russia poses a “significant threat” to western European democracies following a suspected “terror plot” near an airbase in England over the weekend.

Five men were arrested in Whelford, Gloucestershire, in the early hours of Sunday near the RAF Fairford base, which is used by the US Air Force (USAF).

The suspects, who are all British nationals aged in their 20s and from London, were initially arrested on suspicion of explosives offences and later terrorism.

Speaking to reporters on Sunday, US President Donald Trump said the suspects had been looking to ‌do “big damage”.

A villager in Whelford dialled 999 after she saw three vans and a group of masked men near the base, and dozens of homes had to be evacuated as bomb disposal teams were called in.

Police were understood to be investigating if any potential plot could be linked to Iran, which has used proxies to carry out crimes on British soil in the past.

On Monday, Iran’s London embassy said it “categorically rejects” the nation had any involvement in the suspected RAF Fairford bomb plot.

Counter-Terrorism Policing (CTP) said that multiple new lines of inquiry have emerged after investigators were working at the scene overnight.

Speaking about the incident from the Port of Montrose on Monday, the Scottish First Minister said it was “clearly obvious” Russia poses a threat.

“Issues around the security at particular military establishments is a matter for the United Kingdom Government but, more generally, I am concerned about the context in which we are operating,” Mr Swinney told the Press Association.

“It is clearly obvious that Russia poses a significant threat to western European democracies, and it’s important that we have all of the infrastructure in place, all of the monitoring, all of the effective defence capability, to ensure that we are able to withstand these risks and these threats, and that is an issue which is the responsibility of the United Kingdom Government.

He added: “I will hold them to account on that, but I will also take the steps to make sure that the critical national infrastructure of Scotland is safe and secure for all of our requirements in the years to come.”