Prime Minister James Marape said the news was “one of the saddest days of my life”, and promised to hunt down the killers. Philip Undialu, governor of Hela Province in the central highlands where the attack took place on Monday, said: “It’s a very sad story.” Images shared on Facebook showed the victims of the attack, including several children, wrapped in cloth and laid on palm leaves by the side of the road.
The cause of the killings is not yet known but is part of a long-running conflict that has been active for years.
The people targeted in this attack had offered shelter to victims of a similar bout of violence several weeks ago, according to Mr Undialu.
Mr Undialu said: “It was a retaliation of a previous attack. It was a very sudden attack.”
He added: “Both attacks were made in an innocent community where people were not expecting it and all of us are in a state of shock.”
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The fresh attacks bring the death toll up to 24 people.
Mr Marape said he was “coming for” the killers.
In a Facebook post, he said: “In memory of the innocent who continue to die at the hands of gun-toting criminals, your time is up.
“Before I had someone else to report to now I have no one else to report to but the innocent you kill.
“I am not afraid to use the strongest measures in law on you. I am coming for you.”
Mr Marape, who became leader in May, blamed a lack of police on the ground as a major problem in a region that has struggled with violence for years.
Papua New Guineas’s highland regions are very remote with communities based around tribal customs rather than central government.
The disputes are often over land allocation and the distribution of resource wealth.
ExxonMobil was forced to halt construction on a natural gas pipeline last year because of unrest.