Police are investigating the robbery of two security guards in Airdrie early on Tuesday morning.

The men were replenishing the ATM at the Clydesdale Bank in the town's Forrest Street at around 7.20am when they were approached by two other men.

They threatened the security guards, and made off with a container containing a five figure sum of cash. they fled in a silver coloured five series BMW with a registration that begins with MD07.

The security guards were uninjured in the incident.

Detective Inspector Tom Carty from Strathclyde Police said: "This is the second time in four days that a silver coloured BMW bearing the prefix MD07 was used in similar circumstances.

"On Friday 6 November an attempt was made to rob security guards at a Post Office in Birkhill Road, Hamilton.  Fortunately they were unsuccessful.  The suspects made off in a silver coloured BMW with the same registration.  Our enquiries have revealed that these plates were stolen from a BMW 5 series car.

"I believe that the security guards were deliberately targeted and those responsible must be caught.  It is totally unacceptable that security staff who are earning an honest living, are being threatened by these individuals."

Detectives are asking for anyone who was in the area at the time of the robbery to get in touch, and anyone who might have seen a car matching the description.