Large cement stones are placed in front of a seaside shopping mall in Busan, southeastern Korea, on Sept. 5 to prevent damage from Typhoon Hinnamnor. Yonhap

Busan, Korea's second-largest city, is making an all-out effort to minimize the damage from the approaching super strong typhoon, officials said Monday, as Hinnamnor is forecast to hit the southeastern port city hardest.

According to the regional weather agency, Busan is expected to enter the strong wind radius of Hinnamnor between 6 p.m. and midnight Monday, while the typhoon is to make landfall after passing 90 km west-southwest of the port city around 6 a.m. Tuesday.

Its intensity at the time of landfall is expected to be strong, the agency noted.

The agency forecast that 100 to 300 mm of rain is to fall in Busan through Tuesday, without ruling out a maximum precipitation of 400 mm in some areas.