A bomb explosion at a mosque in the southeastern Iranian city of Zahedan today left 15 people killed and about 50 wounded, dpa quoted state news agency IRNA as reporting "A relatively strong bomb explosion at the 'Amir Al-Momenin' mosque in Zahedan left 15 people killed and about 50 others wounded," the agency reported, saying the toll was based on preliminary reports. Semi-official news agency Fars also reported separately that security forces found and defused another bomb located nearby the mosque shortly after the blast. The explosion also caused some damage to the mosque packed with worshippers on the occasion of an Shiite mourning anniversary. Zahedan is the capital of Sistan-Baluchestan province, where Iranian security forces often clash with armed bandits and drug- smugglers. Bordering Afghanistan and Pakistan, Sistan-Baluchestan is not only a major transit route for narcotics but also has been hit by a string of attacks and kidnappings blamed on the shadowy Sunni group of Jundollah.