An explosion in Chechnya's capital, Grozny, killed four Russian servicemen and wounded one other Thursday, Russian news agencies reported. The blast occurred within a unit of Interior Ministry forces and the victims were Interior Ministry servicemen, Interfax reported, citing deputy regional prosecutor Nikolai Kalugin. RIA-Novosti reported the same information, citing unidentified law enforcement officials. Interfax quoted Kalugin as saying there was no immediate indication the explosion was an act of terrorism, which suggested it could have been an accident.