North Korea says heavy rainfall has caused dozens of human casualties, destroyed homes and flooded farmland in a northeast area home to a special economic zone.

Pyongyang's Korean Central News Agency said Wednesday torrential rains on Rason city between Saturday and Sunday also destroyed 1,070 houses and 99 public buildings such as schools and hospitals.

It says more than 300 acres of farmland have been flooded.

KCNA's Korean-language dispatch cited "40 human casualties" without elaborating. Similar reports on past damaging rains indicate the figure is the number of dead.

North Korea often suffers heavy damages from summer rains due to poor drainage, deforestation and dilapidated infrastructure.

On Aug. 12, KCNA said torrential rains on South Hwanghae province in southwestern North Korea killed about 10 people and destroyed hundreds of houses.

Wednesday's report didn't mention any damage to Rason's special economic zone.

Established in the early 1990s, Rason combines two small cities, Rajin and Sonbong, near the Chinese and Russian borders.

It's one of the special economic zones where North Korea has been attempting to lure foreign investment for the past two decades, but to poor success. During a visit to the area by The Associated Press in late 2013, Rason hosted 150 foreign companies from 20 countries.

International trade sanctions imposed over North Korea's nuclear and missile programs limit activities in the special economic zones.