AN ARMED gang held up security guards and staff at a Tesco store on Teesside today, escaping with a "significant'' sum of money.

Detectives are not saying whether the raid on the Tesco shop in Parliament Road, in the centre of Middlesbrough, is connected with three other professionally organised robberies on Tesco stores since last November.

It is understood noone was injured in today's attack, although there are reports the robbers were carrying knives and machetes.

A spokeswoman for Cleveland Police said: "A number of people who had their faces covered threatened staff from the store and from a security vehicle which was delivering cash.

"It is not known how many criminals were involved in this offence and it is believed they had hand held weapons though no firearms were produced. No one was injured during the robbery, though a number of people present were understandably shocked.'' The robbers made off with a "significant'' but undisclosed amount of money in a number of cash boxes, shortly after 7.20am today (Monday).

Detectives want to trace two cars in connection with the Middlesbrough raid which could be connected to four other hold ups - three at Tesco stores - since last November.

A spokeswoman for Cleveland Police said last night: "We are aware of previous incidents.'' A silver VW Golf bearing false registration plates V131 DTN was used during the Middlesbrough raid. and detectives say it is likely to have been in the town centre area prior to the robbery.

Police also want to speak to the driver of a black S Class Mercedes seen in the area at the time of the offence. The car may have been abandoned in the area.

A female security guard was held at gunpoint and forced to hand over money in a raid at Tesco, in Eaglescliffe, near Stockton, on November 16.

The robbers got away with money, believed to run into five figures.

A security guard was held at gunpoint in Sainsbury's, in Bishopton Road West, Stockton, on February 5.

A female security guard was threatened with a sledgehammer by two armed men wearing ski masks as she was filling a cash machine Tesco Express store, in Norton, near Stockton at about 7.25am on February 14.

Last month three men attacked security guards at the Tesco store in Acomb Wood Drive, York, and escaped with a large amount of money.

Anyone with information about today's robbery is asked to contact Cleveland Police in complete confidence.

An incident room is to be set up. Officers can be contacted on (01642 326326