SEOUL, South Korea — The most destructive wildfires ever to hit South Korea were almost contained, authorities announced Friday, after rain and cooler temperatures helped fire crew put out the blazes that have killed 28 people and razed vast swaths of land since last week.

Forest fires have swept eight cities and counties in Korea’s southeastern provinces, wreaking havoc and destruction. The long-awaited rain that fell Thursday was minimal, and there’s no forecast for additional rain for at least 10 days,

South Korean firefighters were able to fully contain the wildfires that have ravaged the southeastern part of the country and left 30 dead, officials said, while authorities began a joint investigation into the cause.