Finland has removed a cargo of 69 missiles found aboard a merchant ship that docked in the country and allowed the vessel to leave, transport safety officials said Monday.

The Thor Liberty was detained on December 15 in Kotka, southeast Finland, and was later found to be carrying 150 tons of explosive material, as well as the surface-to-air Patriot missiles and missile propellant charges.

"A Trafi check on 26.12.2011 has revealed that the improperly loaded explosive material has been offloaded from the vessel, with the exception of two properly loaded containers, and the detention order has been lifted," the Finnish Transport Safety Authority Trafi said in a statement.

However Trafi noted that the ship was still unable to continue on its journey since Finnish customs had placed the Ukrainian captain and first mate under a travel ban pending an investigation into the missiles.

Trafi added that customs had also impounded the explosives still on board the ship in two containers.

The missiles, discovered Wednesday on the British-registered ship, were bound for the Chinese port city of Shanghai, according to Finnish police.1

Finnish customs are investigating the case as one of illegal export of defence material.

A German defence ministry spokesman said the Patriot missiles, produced by US firm Raytheon, came from the German military and were destined for South Korea.

He said it was a "legal sale on the basis of an accord between two states at the government level". He said the transaction had received an official export authorisation and was reported to customs authorities.

However Finland said Friday it had not received the paperwork required from Germany.