Police killed four rebels in heavy fighting in Russia's Dagestan region on Saturday and a suicide bomber wounded three policemen in neighbouring Chechnya as militants pressed a campaign against Kremlin rule, Reuters reported.
On Friday, a suicide bomber blew himself up in the third region currently suffering insurrection -- Ingushetia -- killing one and wounding at least five.
A series of suicide bombings and armed attacks on security forces in the mainly Muslim regions of Chechnya, where Russia has fought two separatist wars, Ingushetia and Dagestan have shattered a few years of relative calm in the North Caucasus.
On Saturday, Russian security forces said they had completed a military operation in Dagestan's main city of Makhachkala, having killed four people suspected of complicity in the murder of senior member of the local prosecutor general's office, Interfax news agency reported.
In Chechnya's capital Grozny a suicide bomber blew himself up when police tried to arrest him, Interfax said. Two of three policemen wounded were in grave condition.
Growing turbulence in the North Caucasus has become a major headache for the Kremlin, which is worried violence could spill over into other parts of Russia -- a vast country spanning 11 time zones, which is home to some 20 million Muslims and dozens of nationalities.