UK Prime Minister Andy Burnham said the government believes the Iranian state was involved in the weekend incident near RAF Fairford, a British base used by US bombers for strikes on Iran. “There are strong indications that Iran played a part in what happened over the weekend at RAF Fairford,” he told the BBC on Wednesday, while stressing that the police investigation remains “ongoing, complex and serious.”

Burnham defended the release of five suspects, saying they were subject to “the strictest possible bail conditions.” UK officials had explained the circumstances of their release to US counterparts, he said, following President Donald Trump’s criticism of the decision. “I have complete confidence in the way British security services are handling this,” Burnham said, adding that Britain was working closely with the US.

The five men, British nationals aged 23 to 25 who live in London, were arrested on Sunday on suspicion of explosives offences and preparing a terrorist act, then released on police bail on Monday. Police found petrol but no improvised explosive devices in three vehicles searched near the base. The men remain under investigation, with restrictions on their movements and contacts. Iran’s embassy in London has denied involvement, calling attempts to link Tehran to the incident “unfounded and malicious speculations.”