A fire broke out at the ancient Vasai Fort in Maharashtra's Palghar district on Monday night, an official said today. No casualty was reported and the structure also did not suffer any damage, he said.The blaze erupted around 9 pm when some drug addicts were sitting in the fort compound. One of them apparently threw a burning cigarette on the dry grass which caught fire. The blaze then quickly spread in parts of the premises, a fire official said. 'There was no casualty. Some trees in the premises were destroyed, but the structure was not damaged,' he said.