Police have issued a warning for prospective Gumtree customers to be careful who they do dealings with, after a series of violent encounters left buyers black and bruised.

Three men who responded to an advertisement on the website for the sale of a mobile phone had arranged to meet the sellers at about 8:40pm on Saturday.

But when they arrived at the prearranged location in Kangaroo Point, Brisbane, the men were met by four males who accepted their money and suddenly turned hostile,  reports.

The pseudo sellers allegedly assaulted the buyers, beating them with large sticks and threatening one of them with a knife in demand Slot Online Terbaik 2022 of more money, which they received.

The victims fled to a taxi and locked themselves inside while their assailants damaged the vehicle with their makeshift clubs, before eventually splitting the scene.

A similar incident occurred just hours later, police say, when a man attended a rendezvous in the nearby suburb of Cooper Plains at about 10pm - also under the pretext of purchasing a mobile phone.

Upon meeting the two male sellers and conversing with them face-to-face, the buyer allegedly asked to see some identification and a receipt for the phone.

He was subsequently set on by the two men, along with a third attacker, who punched him in the face and assaulted him with a stick.

The gang of thieves also allegedly robbed the victim of his personal property before fleeing.

Police say they believe the two incidents are linked and investigations are continuing. 

All four victims received cuts and bruising to different parts of their bodies.