Evacuation began one and a half days before the accident was publicly acknowledged by the Soviet Union. In the morning of 28 April, radiation levels set off alarms at the Forsmark Nuclear Power Plant in Sweden, over from the Chernobyl Plant. Workers at Forsmark reported the case to the Swedish Radiation Safety Authority, which determined that the radiation had originated elsewhere. That day, the Swedish government contacted the Soviet government to inquire about whether there had been a nuclear accident in the Soviet Union. The Soviets initially denied it, and it was only after the Swedish government suggested they were about to file an official alert with the International Atomic Energy Agency, that the Soviet government admitted that an accident had taken place at Chernobyl.