German Defence Ministry officials added customs documentation was in accordance with local regulations.

The confiscated missiles have been moved into storage by the Finnish Defence Forces.

A Finnish pilot assisted the Manx-flagged M/S Thor Liberty on December 9, following a request for help during heavy seas.

Wednesday's seizure by Finnish Customs officials of a cargo of explosives and high-tech missiles aboard the ship has aroused a number of questions. It is being asked why such a valuable cargo was poorly packed and shipped with faulty documents.

Their journey was interrupted when a spot check of the cargo aboard the vessel showed that the shipment lacked a permit from the Ministry of Defence that is required for the export or transit of military material.

Customs and police turned their attention to the ship after being informed by the Finnish Transport Safety Agency (TraFi) that it had received advance information that it was possibly carrying explosives. Both the vessel's Ukrainian captain and first-mate are currently assisting police with their enquiries.

Arms shipments transit Finnish territorial waters regularly, but few ships with such cargoes sail without the proper documentation.

"Exceptional incident"

"This incident is exceptional because of the amount of the materials and the type. Personally I cannot remember a case of this magnitude in recent years," head of Finnish customs anti-crime unit Petri Lounatmaa told YLE.

The transport of explosives back and forth across the Gulf of Finland has raised safety concerns. Emergency Services in Kotka set up a one-kilometre restricted zone around the vessel while its cargo was being handled by officials. Even so, the ship had already carried some 160 tonnes of improperly secured explosives across the Gulf of Finland without informing anyone.

"When this huge amount of explosives are being transported and safety measures are not observed, it does indeed arouse suspicious and concerns," says Lounatmaa.

Finnish Defence Forces to move missiles

The Finnish Defence Forces have started moving the impounded Patriot missiles to another site. Police say they are being transferred to a special storage facility for explosive materials.

Police add that all security measures are being adopted to ensure the safe transfer of the cargo.

Lengthy licence process

Return of the missiles from Finland will require acquisition of a Ministry of Defence permit. The Ministry says no applications to transport missiles have been received by Finland over the past decade.

According to the Defence Forces, the vessel should have applied in advance for such a permit, the granting of which is considered in accordance with Finland’s foreign and security policy. Finland needs to know what kind of arms are transported through the country and to where.

A transit licence for the missiles could have been granted, as no export ban exists for such consignments to South Korea.

The Foreign Ministry says it is not participating in the case of the German missile consignment. Markku Virri, the Ministry’s Arms Supervision Manager, says they play a role in the granting of defence export licenses. However, he added no contacts between Germany and Finland had taken place over the missiles consignment.