Tuesday marked the beginning of K-pop sensation Jin's 18-month mandatory military duty in South Korea, ushering supergroup BTS and its legion of fans into an uncertain new era.

Jin reported to a boot camp near the country's border with its nuclear-armed neighbor, becoming the first member of BTS to enlist. He is the eldest member of the group, and his six bandmates will join the military in the coming years, meaning BTS will go on a sabbatical for several years.

The singer, whose real name is Kim Seok-jin, reported to a training facility in Yeoncheon where frontline troops are stationed as a deterrent to North Korea. early Tuesday morning.

Before being assigned to a military unit, he will undertake five weeks of basic training, which will include rifle shooting, grenade tossing, and marching.

The South Korean defense ministry informed NBC News that over 500 other young men are performing their required military service alongside Jin.

On Sunday, Jin uploaded a picture of himself sporting a military buzzcut to the online fan portal Weverse. Before joining the camp, he also left a note for his followers saying, "It's time for the curtain call."

Before entering the base, he was driven by a small throng clutching photographs and posters bearing his image.

BTS requested that its fans stay away from the training facility to prevent overcrowding. Recently, 153 people perished in a crush during Halloween festivities in Seoul.

According to a representative for South Korea's defense ministry, some 300 officials from the military, local government, and affiliated organizations were deployed to the camp on Tuesday to assure the safety of the place as Jin arrived.

This month, Jin reached 30, sparking a heated national discussion over whether he should enlist.

All able-bodied men between the ages of 18 and 28 in South Korea are required to serve in the military for at least 18 months. As a well-known K-pop artist, Jin was allowed to postpone his mandatory military duty until he was 30.

Across the globe, millions of BTS fans who call themselves the "army" are mourning the band's sabbatical.

Gurpeet Dhillon, a 25-year-old from Hong Kong, told NBC News, "It was sudden but not unanticipated." "I applaud their decision to put their country first and cease delaying their necessary military service," said Dhillon, a BTS superfan.

"2025 will be a long wait, but I know that we, the 'army,' will all be waiting for them to reunite as BTS," she concluded.

South Korean law does permit unique exemptions from mandatory military duty for sportsmen, traditional singers, and others who contribute to the prestige of the nation. Prior to the October announcement that the band would enlist, there was disagreement as to whether worldwide K-Pop stars should also be eligible for such privileges.

A pop culture pundit, Jung Duk-hyun, told the Associated Press that those in the pop culture industry face a few obstacles and unfairness in comparison to those in the pure art industry and athletes. "This is likely to remain a contentious issue, so I question if it must be rehashed repeatedly."

The country's defense minister, Lee Jong-sup, stated in August that serving BTS members will likely be permitted to continue practicing and join non-serving BTS members on overseas group tours.

In October, Jin released "the astronaut," his debut solo single. During Jin's absence, the six younger members of BTS will pursue individual projects, and the group will reunite in 2025, after all, seven members have completed their military service, according to their label, Bighit Music.

BTS has much more to offer in the coming years, according to the label.