It was a tale of just two economies when the 13th Pyongyang International Trade Fair opened in the North Korean capital on Monday, with two-thirds of the exhibitors domestic firms, and almost all the others Chinese.

Eight sets of progressively tighter United Nations Security Council sanctions imposed on Pyongyang over its nuclear and ballistic missile programmes have left its economy progressively more isolated.

The latest, passed earlier this month after its sixth atomic test -- which it said was a hydrogen bomb -- bans all joint ventures with North Korean entities, with just a few exceptions, and requires existing ones to be closed within 120 days.

The only European firm at the show was Italian shipping company OTIM, which in 2001 was the first EU freight forwarder to open a representative office in Pyongyang.

Initially business was good, said company president Mario Carniglia, but "then the sanctions came and it became more and more difficult".

Now the firm mostly handles inbound humanitarian shipments under UN and European Union aid programmes, with its commercial cargoes "practically nil at this stage".

Chinese customs inspections were becoming increasingly strict, a colleague added.

Among the few North Korean items still being exported to Europe, said Carniglia, were spare parts for accordions, a musical instrument that is unusually popular in the North.

"Just parts because if it is a complete accordion it is considered a luxury good and you cannot import it in Europe."

Russian ambassador Alexander Matsegora told AFP that unlike in the past, there were no Russian companies taking part. "Maybe they have not much interest in this market."

Some foreign firms were doing business with North Koreans, he said, but "most of those companies are of Chinese origin".