ARMED police swooped on the village of Cronton as gunmen held up a post office.

An armed response unit rushed to the scene at 3.45pm on Tuesday when four masked raiders, one carrying a handgun, burst into the village post office and demanded cash.

Terrified staff retreated to the rear of the store.

One of the offenders grabbed the cash box, which contained money, from the counter and made off on foot.

As the gang ran from the scene the cash box exploded covering them with red dye.

The box was dumped in the middle of the road and the gang escaped empty handed in a silver Ford Mondeo.

One worker sought help from The Black Horse pub next door as the men made their getaway up Cronton Road.

A witness said he considered approaching the gunman.

'I saw four men pile out of the post office wearing dark clothes with hoods and masks,' he said.

'I was about to go over to one of them, but had second thoughts as I saw the gun.'

Another witness added: 'I thought someone had been hurt. Luckily no-one was, but it is becoming a regular occurrence there.' In a separate raid on the same premises in January, robbers used a battering ram to smash security screens and steal bundles of cash.

Inspector Paul Levick of Merseyside Police said: 'Armed officers were deployed but a search of the area and scene came back negative.'