The message was mistakenly broadcast because of "human error" by both the KTWG and KSTO radio stations, according to the Sun, a UK tabloid. The paper neglected to explain how employees working independently at two different radio stations managed to make the same mistake at almost the exact same time.
"The alarm read: 'A broadcast station or cable system has issued a civil danger warning for the following countries/areas: Guam; at 12:25 a.m. on Aug. 15, 2017, effective until 12:40 a.m. Message from KTWGKSTO.'"
A handful of "concerned residents" called police after hearing the warning, according to local media reports. However, the messages' lack of information about a specific threat should've been a clue to listeners that the broadcast was either an error or a test, according to BNO News.
"The unauthorized test was NOT connected to any emergency, threat or warning," Guam Homeland Security and Civil Defense (GHS/OCD) said in a statement. "GHS/OCD has worked with KSTO to ensure the human error will not occur again."
Guam Homeland Security Adviser George Charfauros reminded residents that they should remain calm even in the event of a credible threat because the US government has the "capabilities in place" to safeguard the island.