0456 GMT July 17, 2019
Officials said the deaths occurred in Hela Province – a rugged region in the west of the country – when rival tribes apparently clashed over control of local gold deposits in the mineral-rich soil, AFP reported.
Highland clans have fought each other in Papua New Guinea for centuries, but an influx of automatic weapons has made clashes more deadly and escalated the cycle of violence.
Hela provincial administrator William Bando told AFP on Wednesday that the death toll could rise.
"We are still waiting for today's brief from our officials on the ground," he said, calling for at least 100 police to be deployed to reinforce some 40 local officers.
The incident has shocked both the country and recently appointed Prime Minister James Marape, whose constituency includes the district where the killings occurred.
He vowed more security deployments and warned the perpetrators "your time is up."
"Today is one of the saddest day of my life," he said in a statement. "Many children and mothers innocently murdered in Munima and Karida villages of my electorate."
In the Karida attack, six women and eight children – as well as two pregnant women and their unborn children – were hacked and shot to death in a 30-minute rampage.
PNG tribal unrest
Marape blamed the violence on three related warlords who have been fighting against the Tagali tribe over local gold deposits.
Tribal clashes are a frequent occurrence in Papua New Guinea's highlands, where old rivalries prompted by rape or theft, or disputes over tribal boundaries or resources, often prompt violence.
But this is the most serious incident in years and the government – which has only 40 police and 16 soldiers in the area according to Bando – is struggling to respond.
In nearby Enga Province, a similar surge in violence prompted the establishment of a makeshift military garrison and the deployment of a company of around 100 government soldiers under the command of a Sandhurst-trained major.
But even those forces lack the resources to tackle difficult terrain.