Both countries have been hit hard by heavy rains and flooding in recent weeks, as the latest storm brings landslides, evacuations and power outages
(Recasts and updates throughout with the storm moving across South Korea)
By Sangmi Cha and Sakura Murakami
SEOUL/TOKYO, Sept 7 (Reuters) - South Korea hunkered down as Typhoon Haishen travelled northwards along the country's east coast on Monday, a day after the powerful storm battered Japan's southern islands where four people are missing following a landslide.
The storm, carrying top sustained winds of up to 112 km (70 miles) per hour, cut power to more than 17,500 households in the southern tip of the Korean peninsula as it made landfall in the southern city of Ulsan, the country's weather agency said.
The wild weather uprooted trees and caused landslides near apartment buildings on Geoje Island, off the southeastern tip of the peninsula, according to footage sent by residents to local broadcaster KBS.
At least one person was injured after their car overturned in strong winds in Busan, the country's second largest city, where there was also flooding, the safety ministry said in a statement.
More than 1,600 people were evacuated in preparation for the storm, while more than 76 flights across 7 airports, including Jeju International Airport, were cancelled.
Two nuclear reactors in the city of Gyeongju, around 375 km (235 miles) southeast of Seoul were shut down, according to Yonhap news agency. Entries to national parks and some national train services have been suspended, the ministry said.
In Japan, the Kyodo news agency reported that four people were missing and more than 50 people were injured in the wake of the typhoon.
The four went missing in the village of Shiiba, in Miyazaki prefecture, after a mudslide hit the office of a construction firm, Kyodo said.
Among the injured were a woman who fell down a flight of stairs in the dark and four people who sustained cuts after the glass windows of an evacuation centre were blown in.
Kyushu Electric said about 290,000 houses were still without power as of 1 p.m. (0400 GMT).
Almost 2 million people had been ordered to evacuate the region, which was still recovering from heavy rains and flooding in July that killed 83 people.
Typhoon Haishen comes just days after Typhoon Maysak smashed into the Korean peninsula, leaving at least two dead and thousands without power.
North Korea, which bore the brunt of both Maysak and Typhoon Bavi a week earlier, is also in Haishen's trajectory with the storm expected to draw near the port city of Chongjin Monday afternoon.
Live footage on state TV, a rarity that has now been broadcast for three weeks, showed trees shaking and waves rising in Tongchon county in Gangwon province bordering the South. The state broadcaster reported that all Tongchon residents had been evacuated.
North Korea's agriculture sector is particularly vulnerable to severe weather, and this summer's storms and floods have raised concerns over the country's tenuous food situation.
North Korean leader Kim Jong Un on Saturday toured coastal areas hit by Maysak, and ordered party members to join the recovery effort.
(Reporting by Sangmi Cha in Seoul and Sakura Murakami in Tokyo; Editing by Jane Wardell)