Six Tanzanians were shot dead and seven others injured in an attack carried out by unidentified assailants in a village bordering a region in Mozambique known for jihadist activity, a police official said on Wednesday.
For nearly two years, jihadists have carried out numerous raids in the Mozambique's Cabo Delgado province bordering Tanzania, killing at least 300 civilians and displacing tens of thousands of people.
"The attackers, presumably from Mozambique, gathered the villagers together before opening fire," said Robert Boaz, criminal investigations chief for the Tanzanian police, during a meeting near the attack site in the southeastern district of Tandahima.
"Six were killed and seven were injured," he said.
The attack targeted the village of Ngongo on the Tanzanian side of an island in the Ruvuma river, which forms part of the border between Tanzania and Mozambique, Boaz said.
"The police and other security organs are doing everything to ensure that everyone involved is arrested and brought to justice," he said. "No drop of Tanzanian blood can be spilled with impunity."
According to Mozambican media reports, Tanzanians are among the jihadists operating in the Mozambique's Cabo Delgado.
Tanzanian police chief Simon Sirro said in October last year that Tanzanian "criminals" had fled "to establish their base in Mozambique".
These "criminals", he said at the time, were implicated in multiple killings in 2016 and 2017 targeting police and administrative officials in the eastern district of Kibiti.
The motive for the killings remains unknown, but Tanzanian President John Magufuli suggested in June 2017 that they were religiously motivated, and some blame them on Islamist extremists.