Suspected jihadists attacked a military position on Monday in Boni in the western Tillaberi region near Burkina Faso, the defence ministry said.
Two people including a civilian were also wounded, the ministry said in a statement read out on state television.
"Several dozen terrorists" were "neutralized" and their means of transport were destroyed, it added.
Defence Minister General Salifou Modi in the statement also reassured people of the "unwavering determination of the defence and security forces to continue the fight against the terrorist threat."
Tillaberi is in the vast and unstable "three borders" region between Niger, Mali and Burkina Faso, where jihadist insurgents have carried out attacks for years despite the massive deployment of anti-jihadist forces.
Seventeen Nigerien soldiers were killed in a "terrorist ambush" in the area between Boni and Torodi in August.
Niger is ruled by military leaders who seized power in a July coup, citing a worsening security situation as justification for the power grab.
The Niamey regime also faces violence by Boko Haram jihadists and their rivals Islamic State West Africa Province (ISWAP) from the southeastern region of Diffa near Nigeria.
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