Shop workers locked themselves in a room after a masked man pulled a knife and demanded cash in Ipswich last night.

Suffolk police were called to reports of an attempted robbery at the East of England Co-op in Pinewood, Ipswich, at around 9.45pm on Thursday.

A force spokesman said a masked man had entered the store and approached one of the staff members in an aisle and drew a “large knife”. “He stated that he wanted cash from the till,” the spokesman added. “Staff members were able to secure themselves in a locked room and nothing was stolen.”

The offender was seen heading in the direction of Belmont Road. The suspect is described as white, around 6ft 2in tall, wearing a black hooded top, grey jogging bottoms and a red face mask. Officers are linking the crime to a similar offence in Essex.

It comes after a number of break-ins and robberies at stores across Suffolk and Essex, many involving the Co-op.

An East of England Co-op spokesman confirmed the armed robbery had happened at its store.

“Incidents like this are never acceptable and we take the welfare of our colleagues, members and customers very seriously,” the spokesman added.

“We are doing all we can to support the colleagues involved in this distressing incident, and are working closely with local police forces to assist in their enquiries.

“All our branches are fitted with CCTV and panic alarms, monitored 24/7 by our own in-house security team, which ensures that assistance arrives as quickly as possible. We have also invested in an increased security presence in-store and will be installing security screens to stores in areas at most risk, along with other security measures.

“Like many businesses, we are concerned about the rise in anti-social behaviour, burglaries and robberies and have a second meeting scheduled with senior police officers in our region to once again raise our concerns and discuss how we can work together to reduce incidents like this.”

Armed robbers targeted the Co-op Daily shop in Silver End, Witham, on Wednesday night.

-MORE: East of England Co-Op confirm second serious incident in just over a month at Witham store

Staff at that store had also been threatened with large knives during an incident in February.

And in January, armed robbers used a hammer and a pole to push staff at the Witham store to the floor.

A spate of ram raids at Co-op stores in the region led to reward being offered.

The reward was doubled to £40,000 after a ram raid at the Co-op Foodhall store in Lavenham on December 21.

Any witnesses are asked to contact South CID at Landmark House on 101 quoting reference 18456/18. Alternatively contact the charity Crimestoppers anonymously on 0800 555 111.