Two police officers were killed after unidentified assailants opened fire on them in Russia's North Caucasus republic of Kabardino-Balkaria, a police source said, RIA Novosti reported.
The armed attack was aimed against the head of the criminal investigation department of the republic's Elbrus district and took place at about 22:00 Moscow time (6:00 p.m. GMT) on Wednesday, he said.
The officer was killed in the assault and a female investigator was wounded and later died in a hospital.
Terrorist attacks and shootouts with police are common in Russia's troubled North Caucasus republics, especially in Dagestan and neighboring Chechnya and Ingushetia.
The Kremlin has vowed to clamp down on militant groups while stepping up efforts to boost the local economy.