Seoul - K-pop boy band BTS is reuniting on Saturday for a concert in the southern port city of Busan, which the city and the South Korean government hope will help win a bid to host the World Expo 2030.

Titled 'BTS in BUSAN' is a free concert set to take place at 6 p.m. local time (0900 GMT) and is expected draw about 100,000 fans to the stadium and designated areas in Busan, over 300 kms (190 miles) southeast of capital Seoul, according to the Busan Metropolitan City.

The concert comes after the seven-member band announced a break in June from group musical activities to pursue solo projects, raising questions about the band's future.

With BTS' oldest member, Jin, who is turning 30 next year, facing South Korea's mandatory military service, the country's defense minister said in August that BTS might still be able to perform overseas while serving in the military.

Under a 2019 revision of the law, globally recognised K-pop stars were allowed to put off their service until 30. Military service is hugely controversial in South Korea where all able-bodied men aged between 18 and 28 must fulfil their duties as part of efforts to defend against nuclear-armed North Korea.

Four countries, including South Korea, Italy, Ukraine and Saudi Arabia, have submitted competing candidatures to organise World Expo 2030, according to the expo organising body Bureau International des Expositions (BIE). The host country of the World Expo 2030 is expected to be elected next year.

In July, K-pop sensation BTS was named as the official ambassadors for the World Expo 2030 in Busan.

BTS made its debut in June 2013 and became a worldwide sensation with its upbeat hits and social campaigns aimed at empowering young people.

Last year, BTS became the first Asian band to win artist of the year at the American Music Awards. The group met U.S. President Joe Biden at the White House in May to discuss hate crimes targeting Asians.

(Reporting by Heekyong Yang; Editing by Michael Perry)