Russia ? Militant attacks and gunbattles across Russia’s violence-plagued North Caucasus left seven people dead Saturday, including the second suicide bomber to strike in less than 24 hours, law enforcement and emergency officials said.

The bomber blew himself up after approaching police on patrol near a school in Grozny, the capital of the war-scarred Chechnya province, said Marat Prokopenkov, a spokesman for the Emergency Situations Ministry in southern Russia. He said three police were wounded, two severely.

The provinces along the Caucasus Mountain ridge that marks Russia’s southern border have suffered a surge in suicide bombings and other attacks in recent months. The spike in violence is shaking the Kremlin’s grip on the heavily Muslim region nearly a decade after large-scale fighting ended in the second of two devastating wars against separatist rebels in Chechnya.