Police in the capital of Papua New Guinea have warned residents to be wary of violent clashes.
Two men have been arrested after a man was beheaded in Port Moresby during a tribal dispute on Saturday.
The incident comes weeks before the expected deployment of about 2-hundred and 30 Australian police and about 70 public officials to PNG.
Police say a Goilala man stabbed a fellow market stallholder, from the Tari region of PNG's Southern Highlands.
Then a group of Tari men captured and allegedly murdered a Goilala man.
The Koki market area has been closed indefinitely, and police are appealing to each tribal party to suspend revenge attacks.