The foreign ministry says that Swiss experts will not be sent to Lebanon to help investigate the assassination of former Prime Minister Rafik Hariri.
But it said that it would intervene if asked to do so by the United Nations. Lebanon, which had asked for help, said that it was shocked by the Swiss decision.
The news came as a UN fact-finding team began enquiries into the death of Hariri. He was killed in a car bombing in Beirut on February 14.
"Taking into account the United Nations mission in Lebanon... the foreign ministry considers, along with the relevant federal authorities, that the framework in which to give a favourable response to the Lebanese authorities should be that of the UN," said the Swiss foreign ministry on Friday.
"Switzerland is ready to make experts available within such a framework if asked to do so by the UN," it added.
The ministry said that its decision had been communicated to Lebanon and to the office of UN Secretary-General Kofi Annan.
Reacting to the news, Rafic Chlala, a spokesman for the Lebanese president’s office, said that the country was shocked by Switzerland’s decision.
But he expressed the hope that a solution could still be found to allow Swiss experts into the investigation.
"We still don’t know how the attack happened, nor which explosives were used," said Chlala.
"The Lebanese state wanted to ask Switzerland, as a neutral country, to help put an end to this ambiguity which has caused so much upset locally," he added.
Lebanon officially asked Switzerland for assistance last Thursday. Media reports in Lebanon suggested that the country had asked for experts in explosives and DNA.
A three-man UN team, led by Irishman Peter Fitzgerald, is due to meet Lebanese officials.
Lebanon has so far rejected calls for an international enquiry but has expressed willingness to cooperate with foreign investigators.
swissinfo with agencies
Former Prime Minister Rafik Hariri was killed in a bomb attack in Beirut on February 14, in which at least 17 others died.
He had been a key political figure in Lebanon for 12 years, after 15 years of civil war.
Hariri was considered the driving force behind Lebanon's economic recovery, but was also accused of increasing the country's debt.
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