Mexican security forces told Reuters the device was intercepted over the training ground on Tuesday because it was not registered.
The intervention was part of a security operation implemented across World Cup host cities that involves the coordination of thousands of personnel and advanced technology.
The heightened measures come as authorities attempt to bolster safety in Jalisco, a state that has faced high levels of insecurity generated by violent criminal groups fighting over drug trafficking routes and other crimes.
While the interruption occurred just as the squad was set to begin sensitive tactical work, Hong noted that the team's primary preparations remained intact.
"It did not impact us significantly, but while we were preparing for the match, that was the most important timing, so what happened was unfortunate," Hong told a press conference.
South Korea are looking to build on the momentum of their 2-1 comeback victory over the Czech Republic to secure a firm grip on the top of the group.
The drone incident added a layer of tension to the high-stakes match at the Guadalajara Stadium on Thursday, where Mexico will look to leverage its status as a tournament co-host.
With a massive home crowd expected to create a partisan atmosphere, Hong emphasised that his players must maintain their composure to neutralise home-soil advantage.
"My players have experienced such matches before, so it will be different tomorrow," Hong said. "We need to control the rhythm and the flow of the match, and then the timing will be important to consider."
