With heavy rain soaking the nation’s central region, the state forestry agency has strengthened its landslide advisories.

The Korea Forest Service said Thursday that as of 6:30 a.m., it has upgraded its landslide advisory by a notch on its four-tier scale from “alert” to “serious,” the highest level, for Daejeon, Sejong, and North and South Chungcheong provinces.

The advisories for Gyeonggi and Gangwon provinces were raised from the second-lowest level, “caution,” to “alert.”

Seoul, Incheon, Busan, Daegu, Gwangju, Ulsan, the Jeolla and Gyeongsang provinces, and Jeju Island will remain under caution-level advisories.

According to the Korea Meteorological Administration, heavy rain advisories are in place for the central region and northwestern parts of North Jeolla Province, where torrential rains of 20 to 50 millimeters per hour are expected.

The Chungcheong region is forecast to see more than 150 millimeters of rain Thursday.