The death toll rose to five in an explosion at South Korea's aerospace plant, Yonhap news agency said Monday, citing the fire authorities.

An emergency call was received at 10:59 a.m. local time (0159 GMT), reporting the blast at the Hanwha Aerospace plant in Daejeon, about 150 km south of the capital Seoul.

The fire authorities confirmed five deaths and two injuries in the accident at the plant of Hanwha Aerospace, the country's leading aerospace and defense company.

Some 30 emergency calls were made to report that the explosion was heard, with rising smoke seen.

The fire authorities issued a level-1 response at around 11:17 a.m. local time and brought the fire under control by 11:49 a.m. local time.

The plant experienced rocket propellant explosions in 2018 and 2019, causing eight casualties.

The police and the fire authorities believed that the explosion occurred on the first floor of the plant for unidentified reasons, planning to investigate the exact cause of the accident.