A gang of five men wielding guns and machetes robbed three people in a flat in Hove at the weekend.
Sussex Police said: “The group broke into the top floor flat in Adelaide Crescent, Hove, at about 11pm on Saturday (13 August).
“They threatened the three men living there, aged 18 and 21, with what appeared to be two black handguns – although it is not yet known if these were genuine or imitation – and machetes and stole a Rolex watch together with some cash in a wallet with bank cards.
“One of the victims, the 18-year-old, required medical treatment for a cut to his head after he was hit.
“One of the suspects is described as black, two are white, one is of mixed race and the fifth is described only as wearing black or dark coloured clothing.
“They made off in a car which had the livery of a Brighton and Hove licensed taxi, probably dark grey, which drove off leaving one of them behind. He ran after the vehicle and jumped in while it was on the move, setting off towards the seafront.
“Inquiries show that the vehicle had recently been sold and is no longer a licensed taxi.”
Detective Sergeant Cheryl Lewendon said: “We are appealing for witnesses or anyone with information to contact us.”
Anyone who can help is asked to phone Sussex Police on 101.