A woman suicide bomber blew herself up in southern Russia's Dagestan Saturday, wounding at least 18 people, including children and several police officers.
Police say the bomber detonated her explosives in the central square in Makhachkala, Dagestan's capital. At least two of the wounded are in critical condition.
The woman was identified as 25-year-old Madina Alieva, a widow of two slain Islamists. Islamic militants are believed to advise fighters' widows that they can be reunited with their husbands by carrying out a suicide attack. Such bombers are known as "black widow" attackers.
Two other bombings in Makhachkala earlier in the week killed four people and wounded at least 40 others.
Dagestan borders Chechnya and has seen many violent confrontations between radical Islamist fighters and Russian federal forces in recent years. The small republic in the turbulent region north of the Caucasus Mountains was visited last year by one of the bombers accused of the terror attack in the United States last month that maimed and killed runners and spectators at the Boston Marathon.