The Swiss ambassador to Iran, Tim Guldimann, is in Washington this week amid signs of a growing rapprochement between the Islamic state and the West.
Behind the scenes, the Swiss embassy in Tehran has been building bridges, acting as a go-between for Iran and the United States, which severed diplomatic relations after the Islamic revolution in 1979.
Iran was quick to condemn the September 11 attacks on New York and Washington, and both Iran and neighbouring Afghanistan have been at loggerheads for some time.
However, on Wednesday Iran's supreme leader, Ayatollah Ali Khamenei, said Tehran would provide no assistance in the event of a US strike against neighbouring Afghanistan, where Washington's prime suspect for the September 11 attacks, Osama bin Laden, is based.
But Iran's foreign minister, Kamal Kharrazi, said Washington would be justified in taking action if it had evidence that bin Laden was behind the attacks. Previously Tehran had insisted that any US response would have to be under the aegis of the United Nations.
Iranian government angered
Iran is seen as a potential ally because of its hostility to Afghanistan's ruling Taliban movement. The killing of six Iranian diplomats by Taliban forces almost led to war three years ago, and Tehran has been angered by the oppression of the Shia Muslim minority in western Afghanistan.
According to media reports, a letter from Washington has already been passed to the Iran government via the Swiss embassy in Tehran. However both the ambassador and the foreign ministry have refused to comment on the embassy's role, arguing that the situation is too delicate.
Professor Albert Stahel, a political scientist at the University of Zurich, believes Washington currently has two reasons for using the Swiss embassy to act as a go-between for the two countries.
"The United States wants Tehran to open its airspace for American aircraft because they need it if they want to launch operations against Afghanistan," he told swissinfo. "In the longer term, perhaps, the United States is also interested in having a better relationship with Iran."
Guldimann: Seasoned diplomat
According to Stahel, Switzerland is fortunate to have one of the country's "best diplomats" running the embassy in Tehran. Guldimann is no stranger to difficult situations, having previously headed Organisation for Security and Co-operation in Europe (OSCE) missions to Croatia and Chechnya.
Guldimann helped to broker the peace deal that ended the first war in Chechnya and oversaw the country's first multi-party and presidential elections in 1997. He then moved on to Croatia before taking up his present post in the summer of 1999.
As Stahel pointed out, the 50-year-old ambassador, who speaks around a dozen languages, including Russian and Arabic, will be well aware of the need to act as a liaison between Iran and the US and not become involved politically.
"We have always had a good relationship with Tehran," he said. "We have had no problems because we were not involved in any of the problems other states had in the past with Tehran. Politically, it is certainly one of the best relationships when compared to other countries."
Iran is not the only country where Switzerland represents the interests of the United States: the Swiss embassy in Havana houses a US interests section.
Adam Beaumont with agencies