Thousands of survivors of floods that hit a remote corner of North Korea in August are in need of urgent aid as winter sets in, a senior international aid official said Tuesday.

The floods, the worst in North Korea in 70 years, hit near its northeast borders with China and Russia and affected 600,000 people and left 70,000 homeless, the International Federation of Red Cross and Red Crescent Societies (IFRC) said.

"There is still much to do. Many people lost everything," IFRC President Tadateru Konoe said in a news release following a 10-day visit to the isolated country. "They need basic relief supplies to get through the winter months and more investment is needed to restore health services, water supply and sanitation systems together with mass awareness campaigns to guard against the spread of communicable diseases."

Underdeveloped rural North Korea suffers from a lack of proper infrastructure and much of its mountainous terrain has been deforested to make farm land, removing a natural flood barrier.

The country also suffers from very cold winters, meaning people made homeless by the floods are particularly vulnerable.

In September, the IFRC made a $15.5 million emergency appeal to help North Korea's Red Cross Society reach more people with aid, but only 25 percent of the target had been met, the IFRC said.

The U.N. Office for the Coordination of Humanitarian Affairs said in September that according to figures based on government data, 133 people were killed in the floods and 395 were missing.