Robbers threatened staff and customers at gunpoint before escaping with £1,000 in a post office raid.
One man brandished a gun while another climbed over the counter, pushed the postmistress out of the way and grabbed the cash from the till.
Both men then fled the newsagent and post office in Leybourne Parade, Bevendean, Brighton, after the raid at 4.45pm yesterday.
They made off in a waiting getaway car, a red Austin Metro, driven by a third accomplice. The men dumped the car a few streets away in Plymouth Avenue.
It was the second armed robbery at the Bevendean branch in a month.
Two men armed with a sawn-off shotgun and a knife escaped with what police termed a "substantial" amount of cash on March 17.
Three days later, robbers grabbed cash and stamps at Hangleton Newsagents in Hangleton Way, Hove.
Police have appealed for witnesses to call Detective Constable Jenny Abura at Brighton CID on 0845 6070999 or Crimestoppers on 0800 555111.
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