Specialists at the Swedish Nuclear Power Inspectorate (SKI) and Atombesopastnost, a subsidiary of Russia's Federal Atomic Energy Agency (Rosatom), found a large number of the 35 sites on the Kola peninsula to have "insufficient" security measures, it says.

"The illicit trafficking problem is for real," says the report, according to New Scientist.

The magazine released the article to the press on Wednesday ahead of publication on Saturday.

The investigation was completed earlier this year and was presented in summarised form last week at an International Atomic Energy Agency conference on nuclear smuggling in Edinburgh, Scotland, New Scientist adds.

Questioned by AFP, a member of the Swedish investigative team confirmed the existence of the report but refused to give any immediate details about it.

The Kola peninsula, which borders Norway and Finland, is thought to hold the highest volumes of radioactive waste in the world, the article says.