North Korea has released an American missionary who was detained for entering the country illegally.

On Christmas Day, 28-year-old Robert Park crossed a frozen river from China into North Korea.

The American wanted to hand North Korean leader Kim Jong-il a letter calling for the release of political prisoners, the closure of prison camps, the improvement of human rights and Kim Jong-il's resignation.

He was immediately picked up by North Korean border guards and nothing had been heard from him since.

Pyongyang says Mr Park has apologised and has therefore been released. Analysts say North Korea is seeking to improve relations with the US in the hope of a new dialogue.

Robert Park has been flown back to Beijing and will return to the United States.

Last August former president Bill Clinton secured the release of two US journalists held for entering the communist country illegally.

North Korea says it is holding another American for the illegal entry into the country on 25 January. It is not known what his motive was.

Photo: US journalists released from North Korea -ANP