Three police officers were killed and one injured in a special operation in Russia's volatile North Caucasus republic of Dagestan, a military spokesman said.
A local police source earlier said that four militants were killed in the operation, which started at about 9:40 on Friday in Dagestan's eastern Sergokalinsky district, but did not specify whether there were casualties among police.
When police surrounded the house with the suspected militants and advised them to surrender, four women left the building. As the women were being led away, the militants in the house opened fire, killing one officer.
Two others died in the shootout that followed. Another officer was shot in leg and shoulder, his injuries are not life-threatening.
In a separate development, a police officer was killed in Dagestan's capital Makhachkala, a police source told RIA Novosti on Saturday.
"The attackers shot the police officer dead when he was leaving the house of his relative and fled," the source said.
Meanwhile another special operation is ongoing in another Dagestani city, Derbent, near the border with Azerbaijan, where a suspected militant was blocked in a five-storey apartment building.
According to the most recent information, officers of the special police force are currently preparing to storm the building.
Russia's North Caucasus republics, in particular Chechnya, Dagestan and Ingushetia, have seen frequent attacks on police and officials despite the end of a decade-long special regime for counterterrorism operations in Chechnya the last years.
A suicide bomber on a Volga car blew himself up at a market in Vladikavkaz, the capital of the North Caucasus republic of North Ossetia, killing at least 17 people and injuring more than 160.
The bombing is the latest in a series of terrorist attacks that have rocked the troubled North Caucasus in recent weeks, including a suicide attack on a military camp in Dagestan.
Last Sunday, a car packed with explosives and driven by a suicide bomber detonated near the Dagestan's town of Buinaksk after ramming the gates of a military unit. Five people were killed in the bombing. Later, a second bomb exploded in Buinaksk on the way of police officers heading to the site of the first blast.