North Korea has begun in earnest to rebuild the city of Ryongchon after a deadly train explosion last Thursday flattened hundreds of homes and reduced a large part of the city to rubble.

North Korea's Central Broadcasting Station said work is under way to completely refurbish the town, including construction of modern living quarters and public buildings.

The broadcaster said aid workers are working night and day to complete rehabilitation efforts by the earliest date possible, adding that some portions of damaged railways and roads have already been restored.