Fresh evidence emerged yesterday of human rights abuses in North Korea, with satellite pictures showing slave labour camps where prisoners are said to be tortured, raped and murdered.

A flurry of revelations this week has attracted fresh scrutiny of the plight of North Korea's 22m people, trapped in one of the world's most brutal military states.

Accounts of life inside North Korea's prison camps were documented yesterday in areport published by Christian Solidarity Network, a UK-based human rights group.

"The treatment of prisoners in North Korea represents one of the worst abuses of human rights we have ever documented," said Mervyn Thomas, chief executive of CSW.

Earlier in the week, the first visual evidence of North Korean labour camps was published in the Far Eastern Economic Review.

The magazine used a commercial satellite company to obtain pictures of a camp in Haengyong in the north-east, near North Korea's borders with China and Russia.

A former prison guard who defected to South Korea identified the camp for the magazine and described how inmates were forced to work long hours in factories, fields and coal mines, with beatings and executions inflicted on rule-breakers.

People are sent to camps as punishment for dissent against North Korean leader Kim Jong-il or his military regime, according to defectors.

South Korean and US intelligence agencies have long been rumoured to possess satellite pictures of the camps but the evidence has never been made public.

Washington has stepped up pressure on Pyongyang since the rogue state admitted in October that it was developing nuclear weapons.