Swiss to destroy papers in intl nuke smuggling case

* Documents smuggled to Iran, Libya, North Korea

* Follows IAEA advice to keep designs from "bad hands"

By Laura MacInnis

GENEVA, June 24 (Reuters) - Switzerland said on Wednesday it would destroy bomb designs and other sensitive documents seized from a Swiss man accused of being part of an international nuclear smuggling ring.

Thousands of papers were confiscated from Urs Tinner, who is being prosecuted for his suspected role in a trafficking network run by Pakistan's Abdul Qadeer Khan, who in 2004 admitted to leaking nuclear secrets.

The Khan network trafficked nuclear materials, equipment and know-how to Iran, Libya and North Korea for about two decades. Its leader was released from house arrest earlier this year on the order of Pakistan's High Court.

In a statement posted on the federal government's website, Swiss authorities said they had agreed with the International Atomic Energy Agency (IAEA) that documents related to uranium enrichment or atomic weapon design posed a risk.

Switzerland, which is not a nuclear power, is not authorised under the global Non-Proliferation treaty to possess documents related to nuclear weaponry.

The Swiss were told by the IAEA they could either transfer the files to one of the five nuclear powers allowed to possess such documents -- the United States, Britain, France, China and Russia -- or destroy them.

"The IAEA estimates nevertheless that the destruction of these documents is the surest solution to preventing this information from falling into bad hands," the Swiss statement said. "For reasons of sovereignty and in order to satisfy the requirements of security policy, the Federal Council chose this last solution."

Switzerland has been struggling for years about what to do with the documents, and has previously announced plans to destroy some sensitive computer files. It said on Wednesday that key documents would be held in a secure location for the duration of Tinner's trial and then destroyed when it ends.

In Vienna, IAEA spokesman Marc Vidricaire said: "The final decision to destroy the documents was a matter for the Swiss government. I can confirm that the agency gave them advice."

IAEA investigators helped break up the Khan network but have been barred by Pakistan from interviewing him to help resolve questions about Iran's disputed uranium enrichment programme, which got off the ground with the help of Khan agents.

Tehran has repeatedly said it is enriching uranium solely for electricity generation, but Western powers suspect that it is actually working toward creating nuclear weapons capability and would want to build atomic bombs. (Additional reporting Mark Heinrich in Vienna; Editing by Matthew Jones)