A police officer in Macomia district, about 100 kilometres south of Antadora village, the scene of the attack, confirmed the ambush which occurred on Friday, but gave no details of casualties.
"Police were called in to intervene but it was too late to help the victims," said the policeman who asked not to be named.
"This is the first confirmed attack this year," in restive Cabo Delgado province, he said.
Villagers spoke of between four and 10 people killed when the minibus carrying around 20 passengers travelling from Palma town to the provincial capital Pemba was torched.
"Two children were burned in the vehicle, another was decapitated," one villager told AFP, adding that a man "was decapitated in front of his wife and children".
He said some women were missing.
"Most of the people didn''t survive. The number of those who survived is less than 10," said another villager.
For more than two years, a shadowy Islamist militancy has sown terror staging attacks in the mostly Muslim province.
Branded as "criminals" by authorities, the militants began attacks in 2017 mostly targeting the civilian population, causing several hundred deaths.
But in recent months the conflict has intensified.
On December 6, a military convoy was ambushed in the village of Narere. Between nine and 14 soldiers were killed and three vehicles destroyed, a villager told AFP.
The government has deployed significant reinforcements to the province to counter the attacks, which have delayed the development of vast gas reserves discovered in 2010.
The arrival in September of 200 contractors from the Russian private security company Wagner appears to have changed little.
The violence has been blamed on a jihadist organisation apparently intent on imposing Islamic Sharia law.
The group is usually referred to as Al-Shabaab, despite having no known link to the Somali jihadist group of the same name. (AFP) RCJ