OSAKA, June 18, 2018 (News Wires) - A magnitude 6.1 earthquake shook Osaka, Japan's second-biggest metropolis, on Monday morning, killing three people, halting factory lines in a key industrial area and bursting water mains, government officials and broadcaster NHK said. No tsunami warning was issued. Prime Minister Shinzo Abe said authorities were assessing damage and that its top priority was the safety of residents. Live footage showed burst water mains and a house on fire after the quake hit Osaka, which will host next year's Group of 20 summit, just before 8am as commuters were heading to work. The epicentre of the earthquake was just north of Osaka city, said the Japan Meteorological Agency, which originally put the magnitude at 5.9 but later raised it to 6.1. The quake struck an important industrial area of central Japan. Osaka-based Panasonic said it was halting production at two of its plants - one that produces lighting devices and another for projectors. Daihatsu Motor Co, a unit of Toyota Motor Corp, said it had suspended production at its factories in Osaka and Kyoto while it checked for damage. Japanese media including public broadcaster NHK said collapsing walls had killed an 80-year-old man and a 9-year-old girl, and that another man in his 80s was killed after being crushed by a toppling bookcase. The government confirmed two of the deaths. "We were sleeping and it woke us up abruptly," said Kate Kilpatrick, 19, an American who was staying in a hotel in Osaka when the quake hit. "It was so terrifying because this is my first earthquake. I thought it was a nightmare because I was so confused," she said. "The whole world was aggressively shaking." Kilpatrick, visiting Japan for the first time, said alarms went off almost immediately in the hotel and a loudspeaker told guests to stay away from windows.