The US Embassy in Japan has urged Americans to avoid going to bars in Tokyo's raucous nightlife district of Roppongi due to a surge in reports of drink-spiking incidents there. The number of reports of Americans being drugged in Roppongi bars has increased significantly, the embassy said in a statement released Tuesday. Victims drink drug-mixed beverages and fall unconscious for several hours. They wake up only to realize their credit cards have been stolen, it said. Roppongi, home to more than 330 bars and nightclubs, is hugely popular among foreigners. "If you, nevertheless, choose to participate in Roppongi night life, we urge you to remain extra vigilant of your surroundings and maintain a high level of situational awareness," the statement said.