MOSCOW (Reuters) - A suicide bomber blew himself up in Russias North Caucasus province of Dagestan, wounding at least 26 people, Russian news agencies reported on Saturday. The attacker set off explosives after approaching police guarding a cordoned-off site where security forces had battled with suspected militants hours earlier, Interfax reported, citing a local law enforcement official. The blast late on Friday wounded 13 police officers and 13 civilians, the report said. Other reports said as many as 30 people were hurt. Unidentified assailants gunned down a school principal in her home in Dagestan earlier on Friday, while separate shootouts killed 12 people across the North Caucasus. The suicide bomber approached as area police had cordoned off in a bid to isolate a group of suspected militants, Interfax reported, citing the National Anti-terror Committee. It said two militants and two law enforcement officers had been killed before the operation was suspended after nightfall.