ASHGABAT (AFP) - Turkmenistan on Friday insisted mystery explosions outside Ashgabat were caused by fireworks but unofficial sources said a military arms depot had blown up in a potentially massive accident. An opposition website outside Turkmenistan, one of the world's most isolated states, said the explosions in Abadan, just 20 kilometres (15 miles) outside Ashgabat, killed many people, caused wide destruction and sparked mass looting. Three concurring sources who asked not to be named told an AFP correspondent the explosions took place Thursday afternoon at a military arms depot in Abadan.