TOKYO, Japan - Four people were injured after a suspected gas explosion at a bar caused a fire on Monday afternoon near Shimbashi in downtown Tokyo of Japan. The explosion was reported at around 3:15 p.m. local time as a fire broke out in an eight-story building near the centrally located JR Shimbashi Station, according to the local police department. According to the Tokyo Metropolitan Police Department, four people suffered minor injuries, who were two passersby and two staff from the bar where the explosion reportedly took place. An elevated concentration of gas was reported in the bar located on the second floor of the building, said the police, suspecting a gas leak incident, with more details under investigation. The 52-year-old owner of the bar, who was injured, told the police that he detected a gas or sewage-like odor in the smoking area, and the explosion occurred when he attempted to light a cigarette using a lighter there, national news agency Kyodo reported. At the time of the accident, Xinhua reporters heard the blast while driving past an intersection less than 50 meters away from the scene, and then saw a lot of fragments flying out of a room on the second floor of the building. A burst of smoke was spotted in the room, accompanied by a slight smell of gas before the fast spread of the fire, the reporters said. The reporters saw three injured people escaping via the emergency exit on site, with their hair and clothes partly burned. According to the fire department, the second and third floors of the building were burned down, with some 31 engines dispatched to extinguish the fire. At the time of the incident, the shop had not opened, and no customers were present. The fire department has almost completely extinguished the fire, and the area around the explosion site is now blocked off for investigation. The busy area, home to many offices and restaurants, was 300 meters to the west of JR Shimbashi Station, one of Tokyo's major interchange railway stations and only 10 minutes' walk from the Ginza shopping district.