Heavy overnight rains across South Korea triggered landslides and flooding, forcing the evacuation of more than 600 people in southern regions and submerging roads and buildings Saturday.

No casualties have been reported so far, according to authorities.

Heavy rain warnings were in effect across the southern Gyeongsang region and parts of Gangwon, Chungcheong and Jeolla provinces as of Saturday morning, with more rainfall expected through Sunday, according to the Korea Meteorological Administration.

The Central Disaster and Safety Countermeasures Headquarters reported that 608 people from 377 households in North and South Gyeongsang provinces, Busan and North and South Chungcheong Province were evacuated as of 11 a.m. due to the heavy rains.

The majority of them, 328, were residents of North Gyeongsang Province.

Most of the evacuees -- 480 people from 276 households -- remained displaced, taking shelter in temporary or community facilities, the government said.

Heavy rains also flooded 78 sections of public roads, leading to 15 incidents of soil loss and the collapse of a retaining wall.

A total of 27 private houses were also inundated, impacting nearly 30 private facilities, such as stores and factories.

As of Saturday morning, 67 sections of roads in Gangwon and South Gyeongsang provinces and other areas, along with 48 underground roadways, were blocked due to safety concerns. Additionally, 641 sections of 22 national parks across the nation remained inaccessible.

An average of 175 millimeters of rain drenched South Gyeongsang Province from Friday to early Saturday afternoon, with Changwon, 296 kilometers southeast of Seoul, receiving the highest rainfall at 399.5 mm, followed by the nearby city of Gimhae at 339.3 mm.

In Changwon, a utility pole was reported toppled on a road on early Saturday morning, while old burial mounds partly collapsed at a tombs museum in Gimhae due to downpours.

Heavy rain of about 200 mm also flooded dozens of roads and vehicles across Busan, the country's second-biggest city, and caused a 10-meter-wide sinkhole to open on a road Saturday morning. Two trucks plunged into the hole and overturned.

The interior ministry raised the heavy rain warning level from "caution" to "alert."

Prime Minister Han Duck-soo urgently instructed officials to mobilize all available administrative resources to mitigate rain damage and prepare for further heavy rainfall due to the approaching tropical cyclone Pulasan on the southern coast.

"In cases of anticipated damage, police and firefighters should cooperate to preemptively evacuate residents, while public employees should be dispatched to areas at risk of flooding until the heavy rainfall subsides," he said.

The weather agency said more heavy rainfall may drench the country through Sunday, with up to 100 mm expected in Busan, Ulsan and South Gyeongsang Province as Pulasan approached South Korea.

As of the afternoon, Pulasan was passing between the southern resort island of Jeju and the southern coast, weakening from a typhoon into a tropical cyclone.