BEIJING - China has reduced rail freight traffic to North Korea in recent weeks, holding up some shipments of humanitarian aid to the impoverished country, an aid agency and rail authorities said on Friday.

The move was apparently taken in anger over Chinese rail cars going missing in North Korea, where analysts say they are sometimes disassembled and sold as scrap metal.

"A lot of Chinese rail cars have piled up in North Korea and have not come back," said an official in the cargo division of China's Railways Bureau in Dandong, the Chinese border city through which most freight to North Korea passes.

"So on this side, we reduced the number of rail cars going to North Korea," said the official, who declined to be identified.

Diplomatically isolated North Korea suffered devastating floods earlier this year that wiped out crops and ruined farmland, compounding grain problems in a country that is already chronically short of food.

The freight disruptions were holding up aid deliveries.

"We have 8,000 tonnes of maize and wheat flour that has been purchased and is ready and we are unable to deliver it to the people who need it," said Paul Risley, the Asia spokesman for the World Food Programme.

The food was sorted and bagged but was being held up on the China-North Korea border, he said.

"These delays have postponed critical food distribution for our beneficiaries."

SUSPENSION

An official surnamed Huang at the Railways Ministry in Beijing said rail traffic was normal, but an employee at a shipping company in Dandong confirmed accounts of disruptions.

"There was a suspension from the middle of September but it resumed after the October holiday," said the employee at the Dandong Tianda International Freight and Forwarding Company, referring to China's week-long National Day break.

ReliefWeb, a United Nations-run Web site, said in an Oct. 15 report that transport of the WFP's food stocks to North Korea were "critically affected by the cessation of cross-border movement of railway wagons from China following a long-pending dispute over delays".

China is one of North Korea's few allies and its major trading partner.

But Beijing was also angered by its neighbour after North Korea defied international warnings and tested a nuclear device last year, and has been frustrated by its failure to convince the North to follow its path of economic reform.

North Korea's economy is so destitute that it lacks power to run its factories at full capacity, there are few cars on its roads and its cities are plunged into darkness at night.