"Six people were shot dead and another was stabbed" in the village of Eringeti in DR Congo's restive North Kivu province, a Congolese military source told AFP.
Eringeti's mayor Leon Baungatho said the assault happened around 5.30 pm (1530 GMT) on Saturday.
"We are still grieving," said regional official Noela Kavivutwiraki. "The army needs to redouble its efforts to prevent surprise attacks from Ugandan rebels."
Thought to be behind a string of deadly attacks in North Kivu, the Ugandan Allied Democratic Forces (ADF) militia stands accused of a number of atrocities in DR Congo.
Congolese authorities and the UN mission in DR Congo, MONUSCO, accuse the ADF of having killed more than 700 civilians as well as combatants in the Beni region from 2014-16.
The ADF is also accused of killing 14 UN peacekeepers in eastern DR Congo on December 7, in the biggest single loss of peacekeepers in nearly a quarter of a century.
The government in January declared it was waging "war" on the ADF and a Congolese militia, the Yakutumba, which is active in South Kivu province, several hundred kilometers (miles) to the south.