An American tour operator has been sentenced to 15 years of compulsory hard labour after being tried by North Korea's highest court for unspecified "hostile acts" against the country.

Kenneth Bae, a 44-year-old tour operator from Lynnwood, Washington state, is said to be a "devout Christian,"

According to a story by Alastair Gale in the Wall Street Journal, activists in Seoul say he was interested in bringing attention to humanitarian issues and may have been detained for possessing images of homeless and orphan North Korean children, known as 'kotjebi'.

The story continued by saying that Mr Bae entered Rason, a North Korean special economic zone bordering China and Russia, with a tour group in November and was detained soon afterward. Mr Bae who was born in South Korea and is based in China.

"Mr Bae has been supporting an orphanage and running a bakery with the North Korean authorities' agreement," said Do Hee-yoon, a member of Seoul-based activist group Citizen's Coalition for the Human Rights of North Korean Refugees. "But he is being detained for taking pictures of North Korean homeless children."

The US State Department has called for Mr Bae's release on humanitarian grounds and says he met with officials from the Swedish Embassy in Pyongyang last Friday. The US, which has no diplomatic links with North Korea, is represented by Sweden in the country.

Gale said that a group led by Google Inc Executive Chairman Eric Schmidt and former New Mexico Governor Bill Richardson in January attempted to meet Mr Bae during a trip to North Korea but were denied access.

Michelle FlorCruz of International Business Times reports that friends of Bae described him as a devout Christian who was based in the coastal city of Dalian, China, travelling frequently between the two countries to help feed the orphans in North Korea.