British counter-terrorism police are questioning two Latvian men arrested inside RAF Molesworth, a base that hosts US and NATO intelligence operations.

The men, aged 36 and 32 and both living in the UK, were found inside the perimeter in the early hours of Thursday. A security patrol had spotted an abandoned vehicle near the site around 10 pm on Wednesday.

Officers then found a small breach in the perimeter fence. The men were first arrested on suspicion of trespass and criminal damage, then re-arrested under the National Security Act for entering a prohibited place for a purpose prejudicial to the UK.

RAF Molesworth, about 100 km north of London, is run by the US Air Force. It hosts the NATO Intelligence Fusion Centre and intelligence elements for US European and Africa Commands.

The arrests follow a separate incident near RAF Fairford on September 27, where seven men were arrested over a suspected plot. The US has since withdrawn its B-1 bombers from that base.

Police say there is nothing so far to link the two incidents, but they are keeping an open mind. The men remain in custody while detectives question them.