Mr Park is a US citizen of Korean ancestry

US activist Robert Park has been freed from detention in North Korea and is heading home to the US, officials say.

Mr Park left Pyongyang and arrived at the main airport in Beijing, China. A US embassy official said he was likely to travel to the US later on Saturday.

Mr Park, a religious activist, crossed into North Korea from China by walking over a frozen river on 25 December.

North Korean authorities said on Thursday they had decided to "forgive and release" Mr Park.

Mr Park was carrying a letter for the North Korean leader, Kim Jong-il, when he crossed the river.

He had reportedly wanted to highlight human rights issues in North Korea, but was said before his release to have admitted his "mistake".

Mr Park, a US citizen of Korean ancestry from Tucson, Arizon, entered North Korea on foot, walking across the frozen Tumen river.

According to his associates, 28-year-old Mr Park claimed he had seen a vision from God of North Korea's liberation and redemption.

On Friday Mr Park was reported to have confessed that he crossed the border because his view of North Korea was based on false Western propaganda.

He now fully realised that religious freedom is fully ensured in North Korea, the country's main news agency reported.

However, the statement has been dismissed as "propaganda" by Mr Park's colleagues.

In addition, analysts say his release could be seen as a goodwill gesture by the North's leader, reports the BBC's Michael Bristow in Beijing.

The two countries have been negotiating on a range of issues, including the North's covert nuclear weapons programme.

Mr Park becomes the third US citizen released in recent months.

In 2009, North Korea detained two US journalists on the border with China.

Laura Ling and Euna Lee were sentenced to 12 years' hard labour but were freed as part of a diplomatic mission spearheaded by former US President Bill Clinton in August after four months in captivity.