A spat between North Korean company Ryongbong Corp,. and Chinese firm Liaoning Xiyang Group has exposed some rarely-seen tensions in the typically harmonious relations between Pyongyang and Beijing, and escalated to even involve the North Korean government itself.

The row between the two companies began over an iron ore mining deal in North Korea.

Wu Xisheng, the Vice General Manager of Xiyang in China, told Reuters that North Korea had unfairly and suddenly raised the prices on land, power, water, and labor, "with the express purpose of driving Chinese partners out."

Wu claimed that his company was "cheated," and told Reuters that "They [North Korea] just don't have the conditions for foreigners to invest. They say they welcome investment but they don't have the legal or social foundations."

The North Koreans struck back, claiming that the Chinese company was "a nightmare" to work with, according to the BBC.

A North Korean spokesman said that Xiyang was "chiefly to blame from the legal point of view," claiming that Xiyang had carried out only 50 percent of its contracted obligations in the four years that the two firms had been working together.

China is one of North Korea's largest business partners; 42 percent of its exports go to China, and 57 percent of its imports come from China, according to the CIA World Factbook.

Just days ago it was announced the Kim Jong-un, the North Korean leader, was asking to visit Beijing to promote further Chinese investment in North Korea. But China has been less than thrilled with Kim thus far, owing to his continued tests of long-range rockets and the alleged development of nuclear missiles by Pyongyang.