

Mario Carniglia, head of Milan-based Otim, an international freight-forwarding company, said in an email interview that his company received 10 containers from the exporter and had them shipped from the North Korean port of Nampo to the Chinese port of Dalian.

In Dalian, Otim placed the containers on the ANL-Australia, which was headed to Bandar Abbas, Iran, Mr. Carniglia said. "The containers left Dalian ... untouched with the same seals put on at the origin," he said.

The U.A.E. stopped the Iran-bound ship in Dubai about a month ago and informed the United Nations that it found various small weapons, including detonators and rocket launchers, from North Korea onboard, according to a U.N. Security Council diplomat.

Under U.N. sanctions imposed on North Korea after it tested a nuclear device in May, Pyongyang is barred from exporting any weaponry. All countries, including Iran, are barred from importing weapons from North Korea, as well. The seizure was the first made under the new sanctions, and could fuel efforts by the U.S. and other Western powers to push for greater economic sanctions against Tehran, if diplomatic outreach fails.

A Security Council official has said the U.N. sanctions committee would conduct its own investigation and was likely to send out letters to all countries that had companies involved in the shipment, including Italy, Australia and France, where ANL's parent company is based.

Citing Italian privacy laws and professional ethics standards, Mr. Carniglia declined to identify the exporter that had sent the containers from North Korea. He said the exporter had provided documents identifying the contents as "Oil Pumping Equipment (Oil Boring Machine spare parts)" when the containers arrived in Dalian.

Australia's minister for shipping said Sunday his government was launching an investigation to see if any Australian laws had been broken, according to the Associated Press. The ANL-Australia is owned by Melbourne-based ANL, a unit of France's CMA CGM. ANL declined to comment, according to the AP.

Write to Peter Spiegel at peter.spiegel@wsj.com