MAKHACHKALA (AP) -- Police in Russia's south killed two suspected militants early Thursday in a counterterrorism operation launched in response to a suicide blast that took the lives of six officers.

An area on the outskirts of Makhachkala, the capital of Dagestan, has been in lockdown since Wednesday's suicide car bombing at a police station as authorities hunted for the masterminds and their accomplices.
Authorities early Thursday gunned down two suspected insurgents who had barricaded themselves inside a house, according to Dagestan police spokesman Mark Tolchinsky.
An hours-long shootout — during which the militants hurled grenades at police — ended when police stormed the building, Tolchinsky said. Two police were wounded in the crossfire, Tolchinsky said.
Tolchinsky refused to confirm reported comments by a spokesman for federal investigators in Moscow that the militants had planned Wednesday's attack.
The suicide car bomber hit a police station on Wednesday at a time when 150 officers were lined up outside on roll call.
City police chief Col. Shamil Guseinov said the six officers who died had prevented a far greater catastrophe by blocking the bombers entry into the compound.