The head of armed policing in Scotland and his deputy are among the officers being investigated as part of a probe into criminal and misconduct allegations.

Assistant Chief Constable Bernard Higgins was suspended on Friday by the Scottish Police Authority (SPA) after allegations were brought to the oversight body's attention by the Police Investigations and Review Commissioner (Pirc).

Superintendent Kirk Kinnell and Chief Inspector Bob Glass were also suspended, the Sunday Mail reported.

Justice secretary Michael Matheson has now said the investigation related to officers based at a firearms unit in South Lanarkshire.

Asked about the newspaper's report on the BBC's Sunday Politics Scotland, Michael Matheson said: "I think at this stage it wouldn't be appropriate for me to start mentioning names of those particular officers.

"But the two which I know that have been suggested are individuals who were involved in the investigation.

"As far as I'm aware, they are two of those who are part of the complaint that's been received by the Pirc that's now being investigated by the Crown Office."

The justice secretary added: "The individuals who are involved in this are related to those involved in the firearms unit within Police Scotland and the training facility which we have at Jackton."

One other officer has been suspended while a further two have been placed on restricted duties.

Matheson said he would not be drawn on the nature of the complaint given the matter was under investigation.

The Scottish Police Federation earlier said the suspension of the officers was "unwarranted".

The Pirc said: "Following receipt of anonymous allegations of criminality by officers, including a senior officer, serving with Police Scotland, the Commissioner referred the allegations to the Crown Office and Procurator Fiscal Service (Copfs).

"This was to allow the Copfs to consider whether the criminal allegations should be investigated by the Commissioner.

"The Copfs decided that an independent investigation should be carried out by the Pitc and this is now under way."

The Pirc is also looking into separate allegations of misconduct against Chief Constable Phil Gormley, who is on special leave.

Mr Gormley and Mr Higgins have both denied any wrongdoing.