* About 10 landmines have not been recovered
* Damage from storms seen at hundreds of millions of dollars
* North Korea also hit by storms (Adds president, details, updates toll)
By Jeremy Laurence and Seongbin Kang
SEOUL, July 28 (Reuters) - South Koreans were cautioned about rogue landmines and explosives on Thursday after scores of deadly landslides in and around the capital swamped homes, a monastery and military sites after the heaviest rainfall in a century, officials said.
At least 77 people died or are missing after landslides and flashfloods swept the Seoul region, home to about 25 million people and the damage bill is expected to run into hundreds of millions of dollars.
The Defence Ministry said about 10 landmines buried near an air defence artillery unit at Mount Umyeon in southern Seoul had not been recovered after a mudslide in the area on Wednesday.
The mines were placed during the 1950-53 Korean War.
Explosives were also swept from an ammunition depot in Yangju, north of Seoul, when it collapsed under the weight of a mudslide. A military official said that all the explosives, including dozens of landmines, had been recovered.
The Joint Chiefs of Staff ordered units to check for any misplaced explosives in the affected regions, but that did not allay residents’ fears. The microblog forum Twitter was abuzz with anxious chatter about the missing landmines.
As more rain battered the mountainous region on Thursday, authorities drafted in the military to help with rescue and clean-up operations.
Hundreds of soldiers wearing helmets and long khaki coats shovelled mud from the site where the landslide slammed into an apartment block at Mount Umyeon. A wall of mud three storeys high hit the building, killing at least 15 people.
President Lee Myung-bak visited the command centre for emergency operations and one of the flood-hit sites.
“If it keeps raining like this, no country in the world can endure this,” he said. “We should raise the bar of safety standards to deal with such natural disasters.”
More than half a metre (19.5 inches) of rain has fallen in the Seoul region since late Tuesday, the weather bureau said, in the heaviest deluge for July since 1907.
The storms also hit secretive North Korea, but there were no immediate reports of damage in its state media. Experts are worried about landslides, as the eroded hillsides are unstable.
Power outages hit Seoul again on Thursday, including a cut in a business district, but the financial services industry and market trading were not affected.
Dozens of landslides were reported around Seoul and streams turned into raging torrents, flooding low-lying areas and swamping thousands of cars.
Some bridges over the main Han River, which runs through the centre of the city, were closed. Train services were also disrupted.
Rescue workers were searching around a Buddhist monastery in Dongducheon, northeast of the capital, where a girl was believed buried under a mudslide. Three others were killed in the area.
Authorities in Seoul said more than 4,500 people had been forced from their homes and many houses were without power.
Emergency services put the death toll at 67, with 10 people missing.
The share price of insurers steadied after tumbling as much as 6 percent on Wednesday, but premiums are expected to rise causing further financial pain for homeowners already stung by rising inflation.
The Financial Supervisory Service, the country’s financial regulator, estimated the bill for car damage alone would be about $38 million. (Additional reporting by Jumin Park and Joonhee Yu; Editing by Miral Fahmy)