Five members of the SAS have been arrested by British military police on suspicion of allegedly committing war crimes while on operations in Syria.

The Ministry of Defence said it would not comment directly on the investigation but defence sources indicated that reports of the arrests, which had been circulating in military circles for some time, were accurate.

An MoD spokesperson said: “We hold our personnel to the highest standards and any allegations of wrongdoing are taken seriously. Where appropriate, any criminal allegations are referred to the service police for investigation.”

Details around the arrests remain limited but the SAS has been actively deployed in Syria for the past decade, engaged in the fight against Islamic State and supporting the Syrian Democratic Forces.

It is not certain that any of the arrests will result in a prosecution, and war crimes convictions of British soldiers are exceptionally rare. But the arrests come at a time when the activities of the SAS in Afghanistan are separately coming under scrutiny in a public inquiry examining claims that 80 Afghans were summarily killed by the unit.

Based in Hereford, the elite force typically operates in absolute secrecy and is ready to conduct risky missions behind the lines and in locations where the UK does not formally acknowledge a military presence.

Government ministers and officials decline to comment on its activities, even off the record, a practice introduced from the 1980s. Its most senior officer, the director of special forces, is only accountable to the defence secretary and the prime minister.