The United States Embassy in Port Moresby says Papua New Guinea police must do more to stop senseless acts of violence.
The Embassy issued a statement at the weekend deploring a brutal attack on three women and one man last week in Mendi in Southern Highlands.
It says the public humiliation, beating, and burning of these individuals with hot rods following accusations of sorcery in the villages of Kave and Kumin is reprehensible.
The Embassy says police must investigate and prosecute those responsible and it says the appropriate resources and attention needs to be directed at addressing these crimes.
It says too often this sort of violence goes unreported and occurs without the perpetrators being held accountable.
The Embassy says PNG's criminal justice system has to ensure better prevention and response and the proper enforcement of existing criminal laws.
And it says the PNG Government, the public, and civil society must say no to violence in their communities and put an end to the stigma that allows accusations of sorcery.