LONDON — The five men arrested on terror charges near Royal Air Force Fairford in the United Kingdom have been released on bail after “extensive interviews,” authorities said on Monday.

The men, who were arrested on Sunday on suspicion of terrorism and explosives offenses, are subject to “stringent conditions on their movement and contact with others,” Laurence Taylor, Head of National Counter Terrorism Policing in the United Kingdom, said on Monday.

The suspects, who have not been charged, “remain under investigation as we explore multiple lines of enquiry,” Taylor said.

The men were detained in possession of three vans close to RAF Fairford, which has long served as a key European hub for the U.S. Air Force and a vital staging point for long-range operations in the Middle East — including in the ongoing conflict with Iran.

Taylor said on Monday, “I know there is significant interest in whether the current geopolitical context has a bearing on this incident.”

“… We are considering this from every possible angle. Including, that this may be activity committed by proxies, or individuals either knowingly or unknowingly, working on behalf of a foreign state,” Taylor said.

Counter Terrorism Policing said all five men arrested were from London, all were British nationals and all were aged between 23 and 25.

Police said earlier they were working to “establish the full circumstances of the activity of those arrested, their knowledge and any motivation behind this incident.”

Speaking to BBC Radio 4 on Monday morning, British Defense Secretary Wes Streeting thanked an anonymous farmer — who also spoke with the BBC — who said she called in the threat after coming across the “hooded and masked” men and vans in the early hours of Sunday morning in the village of Whelford, close to RAF Fairford.

Streeting thanked the tipster for calling in the threat, though said the caller only “had a partial picture” of the situation. “I won’t go beyond that, in terms of commenting on operational security matters,” Streeting added.

The farmer told the BBC she believed authorities had “dropped the ball” in allowing the suspected attackers to get so close to the base.

Streeting declined to give further details on what police and intelligence authorities may have known about the alleged plot, though welcomed President Donald Trump’s praise of an operation that he said had been ongoing for a “long time.”

Trump told reporters on Sunday that the suspects were “looking to do big damage” to U.S. forces present at RAF Fairford. “The arrest in the U.K. was fantastic. Working with Britain, it was an amazing job,” Trump said.

The U.S. military has used RAF Fairford intensively amid the ongoing war with Iran — though so far no connection to Iran has been confirmed or established by authorities. The base has been used by American B-52 and B-1 heavy bombers operating in the Middle East.

When asked of potential Iranian involvement in the suspected plot, Streeting said he was not “drawing a connection with Iran,” before adding, “We know that Iran and their proxies wish to do us harm.”

The Iranian embassy in London denied any involvement in the incident, posting to X to condemn what it called “recent unfounded and malicious speculations published by some British individuals and media outlets.”

“The circulation of such fabricated speculations, particularly in the aftermath of the criminal acts of aggression committed by the United States and the Israeli regime against the Iranian people, will serve no purpose other than to fuel Iranophobia propaganda in the UK,” the embassy said.

“The Islamic Republic of Iran reserves the right to take appropriate legal measures, as necessary, to safeguard the rights and interests of the country and its people in response to misleading and damaging media narratives,” it added.

ABC News’ Victoria Beaule contributed to this report.