A mystery explosion that was reported by locals less than 100 miles from Russia’s capital has left the Kremlin fumbling for answers…The blast occurred in Kolomna near Moscow on Thursday evening, state-run news agency RIA Novosti reported, citing the city administration. Its cause is still unknown. Footage circulating on social media shows eyewitnesses describing the explosion as being preceded by a loud whistle and followed by smoke and a glow. Emergency services later said they had been unable to detect signs of an explosion.