China suspended key rail freight services into North Korea last week after 1,800 wagons carrying food aid and tradeable goods crossed into Kim Jong-il’s hermit state but were never returned.

Absconding with Chinese wagons would be a strange move for North Korea because Beijing is Pyongyang’s closest political ally and biggest provider of food, goods and oil. Analysts monitoring North Korea said Chinese officials had privately complained to them that the North Koreans were dismantling Chinese wagons and selling them back as scrap metal.

The Chinese railway ministry suspended a number of rail freight services into North Korea on October 11, humanitarian agencies operating in North Korea told the Financial Times. The ministry told international aid agencies that it would not send any more wagons into North Korea until Pyongyang returned the 1,800 Chinese wagons.

Tony Banbury, Asia director for the UN World Food Programme, said that the curtailed service had held up the delivery of 8,000 tonnes of maize and wheat already stockpiled in Dandong, a Chinese border town. “We now have significant amounts of food but we can’t deliver it,” Mr Banbury said.

Reliefweb, a United Nations website for aid agencies, reported that the delivery of food stocks into North Korea had been “critically affected by the cessation of movement of railway wagons from China”.

An official with China’s railway ministry said yesterday that it was not aware of any suspension of freight services into North Korea.

But Fu Xue, of the Dandong Tianda International Freight and Forwarding Company, said there had been delays in the return of wagons but that North Korea had asked for permission from China.

North Korea has frequently failed to pay for goods or to pay back debt. It has also long been accused of relying on currency counterfeiting and drug smuggling to stay afloat.

But purloining Chinese wagons would be a brazen move. China is already thought to be disillusioned by Pyongyang’s refusal to embrace economic reform. It was also angered by North Korea’s decision last year to conduct a nuclear test despite Beijing’s objections.

North Korea has a history of not returning vehicles. In 1998, the late Chung Ju-yung, founder of South Korea’s Hyundai Group, donated 1,001 cows to North Korea to make amends for stealing a cow as he escaped from the north as a boy.

Pyongyang said the cows should be transported on Hyundai trucks. The trucks were never seen again.