"A special operation is under way," the commander of Russia's Joint Forces in the North Caucasus, Colonel-General Yevgeny Baryayev, said without giving details.
Chechnya's Prosecutor General Valery Kuznetsov said the gunmen blew up the officers' UAZ minivan before opening fire. The incident took place Tuesday near the village of Dair in the Shatoi district, about 30 miles south of Chechnya's capital, Grozny.
The officers were part of an Interior Ministry Special Operations unit on temporary duty in Chechnya, from Russia's Mordovia region.
Earlier reports said two officers were killed and two were missing, as a search and rescue operation was complicated by nightfall.
Although the latest war in Chechnya officially ended in 2001, which together with the first left up to 100,000 Chechens dead, periodic bombings and clashes between gunmen and federal troops still disrupt the republic's comparative calm, with the violence often spilling over into adjacent regions.
Last week, one police officer was killed and four wounded in a road bridge bombing in Grozny, and another two servicemen were wounded in an armed clash with militants.
Baryayev said last week that about 700 gunmen continue to operate in Chechnya and neighboring regions.
A partial amnesty announced July 15 following the killing of the region's number one terrorist, Shamil Basayev, promised leniency to militants not involved in major atrocities.
A law granting amnesty to militants and servicemen guilty of offenses during the North Caucasus antiterrorism campaign came into force in late September.
More than 300 militants have accepted the surrender offer since its announcement, mainly in Chechnya, according to Nikolai Patrushev, the head of Russia's Federal Security Service (FSB) and the National Antiterrorism Committee.
