"Our service last year stopped three exports which were destined for North Korea. Specifically, they were special machine tools, the pieces themselves and spare parts," security service spokesman Jan Subrt told the broadcaster.

North Korea is interested in obtaining special machine tools because it can not currently construct a small nuclear weapon and delivery system capable of striking a target far beyond its borders, the broadcaster said quoting experts.

It is only capable of producing a large nuclear weapon at the moment, it added.

North Korea's nuclear ambitions have become the focus of worldwide attention following its testing of a nuclear bomb on October 9. The test has resulted in stepped up attempts to bring the closed Communist country back to the negotiating table.

Pyongyang originally committed itself last year to giving up its nuclear weapons in return for security guarantees, the normalization of relations, energy and other aid.

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