Iran's embassy in London on Monday condemned "fabricated speculations" linking Tehran to a suspected plot targeting the Fairford Airbase in the United Kingdom, asserting the accusations would fuel "Iranophobia propaganda". British Foreign Secretary Ed Miliband stated on Monday that the UK must be prepared to "confront" all security threats and vowed to "act against the proxies of Iran". Five British nationals were arrested on Sunday near the base on suspicion of preparing a terrorist act. Investigators are exploring multiple lines of inquiry, including an Iranian-linked motive, a Russian sabotage operation, or an Islamist plot. US President Donald Trump said the suspects had been looking to do "big damage" and had been under investigation by British and US authorities "for a long time". UK Prime Minister Andy Burnham chaired a COBRA emergency response team meeting on Monday.