Red Tabara has been fighting Burundi's government from bases in DRC since 2015.
In a post on social media platform X, formerly Twitter, Red Tabara said it had attacked two Burundian military positions on Sunday night, also seizing weapons and ammunition.
The rebel group said six soldiers had been killed in the attack.
Burundi's President Evariste Ndayishimiye in late December accused Rwanda of hosting and training Red Tabara after a separate attack in which the government said at least 20 people had been killed.
Burundi later closed its border with Rwanda, which rejected Ndayishimiye's allegations.
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