The Voice of America says China has warned Chinese businesses about the risks of investing in North Korea.

The U.S. broadcaster says that a guidebook on investing in North Korea released by the Chinese commerce ministry this year has warned of investment risks that have resulted from economic sanctions on the North and unstable inter-Korean relations.

The guidebook said North Korea is attractive for its abundant underground resources, affordable workforce and low taxes but is also an unstable investment destination due to the nuclear issue, poor social infrastructure and around-the-clock monitoring by the government.

The book also said that the North Korean currency is unstable.