Andy Burnham said there are “strong indications that Iran played a part” in a suspected terror plot near RAF Fairford.

The UK is working closely with US and the authorities have the situation under “the strongest grip”, the prime minister insisted after Donald Trump criticised the decision to release the suspects.

Five British nationals, all in their mid-20s, were arrested on suspicion of explosives offences and terrorism near the military base over the weekend before being bailed under investigation on Monday.

The Gloucestershire site has been used in recent months by American bombers after Sir Keir Starmer granted the US permission to use British bases for “defensive” strikes against Tehran during the Middle East war.

Counter-terror police have said a quantity of petrol but no explosive devices were found in the vans that sparked the security alert near the airbase.

Asked about the case in a series of broadcast interviews on Wednesday, Mr Burnham said: “There are strong indications that Iran played a part in what happened over the weekend at RAF Fairford, but it remains an ongoing, complex and serious police investigation.”

Asked about the US president’s disappointment over the release of the suspects, he told the BBC: “The authorities have this under, as I say, the strongest grip and the closest control, and I can assure you of that.”

Mr Trump said on Monday that the alleged plot “might be” linked to Iran, and added: “I will tell you, I would have said ‘Don’t let them have bail’. I’m surprised that they released them. I wouldn’t have done that.”

The five suspects, all UK nationals, are a 24-year-old from Camden, north London; and a 23-year-old, two 24-year-olds and a 25-year-old from Westminster, central London.Police would not confirm when they are due to answer bail.

Speaking to Sky News, Mr Burnham said he “wouldn’t hesitate” to recall Parliament over the incident if necessary. He chaired an emergency Cobra meeting during Labour Party conference earlier this week.

Residents living near RAF Fairford said they were told to stay indoors hours before police received a call about an alleged foiled bomb plot – with one claiming they were told an attack was about to happen.

has seen messages from a WhatsApp residents’ group chat showing that, shortly before 6pm on Saturday, one resident claimed to be told by armed officers there was intelligence over an “imminent” attack. Another said they were told to make their way home and stay indoors.

In the messages seen by this publication, a neighbour informed other residents they had been stopped by armed police and told to make their way home and stay indoors. The neighbour was not informed why, but the police were reportedly asking people to stay away from the base.

After further replies, another neighbour added they were told to go home because police had received intelligence about a potential imminent attack. They were also told no further information.

Earlier on Tuesday, US Secretary of State Marco Rubio said in a television interview that the suspected plot “clearly involves the hand of a foreign actor”, but refused to provide further details.

Head of UK counter-terrorism policing assistant commissioner Laurence Taylor said on Tuesday that a police response was activated in the early hours of Sunday “due to a range of information that we received”.

Mr Taylor said the five suspects released on bail “remain under investigation” and “must adhere to very strict conditions”.

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