North Korea has sent a letter of appreciation to a South Korean non-governmental organization for sending relief supplies to aid the Ryongchon train blast victims.

The National Economic Cooperation Federation in Pyongyang, which engages in inter-Korean economic exchanges, sent the letter on Friday to Good People, a Christian relief organization in the South, saying its donations were of great help to the disaster-stricken country.

It is the first time Pyongyang has thanked a private organization in Seoul.

The NGO's donations, including 5,000 blankets and medical supplies worth 40 thousand dollars, were delivered on Thursday to Ryongchon.

According to Good People, the Pyongyang-based federation also asked the South Korean group for additional supplies, mainly construction materials to rebuild schools and houses, as well as items for children, such as school bags and shoes.

Good People said they would earnestly consider the North's request.