The American woman held in Iran for over a year has expressed her gratitude to Switzerland, which helped release her.
Sarah Shourd was released on September 14 "on humanitarian grounds" against a $500,000 (SFr 487,000) bail.
On Thursday night, she met US President Barack Obama for the first time since her arrival.
For Obama her release has a “sweet and sour” taste, since her fiancé, Shane Bauer, and her friend, Josh Fattal are still held captive in Evin, the infamous prison in Tehran.
“We remain hopeful that Iran will demonstrate renewed compassion and do the right thing by ensuring the safe return of Shane, Josh and all the other missing or detained Americans in Iran," Obama said.
On Friday, Shourd started the day at the Swiss Embassy where she met Urs Ziswiler, the Swiss ambassador in Washington, before giving a news conference.
“I express my gratitude and great appreciation to the Swiss government, in particular to Ambassador Livia Leu, from the first time we met her, we had a strong attachment to her and she’s always in our hearts,” Shourd told swissinfo.ch.
Switzerland has represented Washington's interests in Iran since 1980, after the rupture of diplomatic relations between Washington and Terehan.
The Swiss ambassador in Tehran, Livia Leu Agosti, visited Shourd four times in the prison of Evin. The three hostages also received visits from embassy staff.
During the news conference in Washington, Ambassador Ziswiler said that Switzerland had interceded hundreds of times in favour of the liberation of the three prisoners since their arrest on July 31, 2009.
“We have been tirelessly in contact with Iranian authorities for more than a year to get their conditions better and to win their release, we work together well with the State Department and we will try everything we can to get the two remaining detainees out,” Ziswiler said.
“In such cases, it’s very difficult to predict what’s going to happen.”
But Sarah Shourd sounded a more optimistic note.
“There are hopeful signs definitely, there’s a warming of relations now, that could be a window of opportunity which we hope leads to more positive gestures from Iran,” she said, without giving further details.
She did not mention either whether her meeting Ahmadinejad a week ago had contributed to her optimism.
“Switzerland, every minute, plays a crucial role in this whole process, was all she said.
Sarah Shourd says she does not know who paid the $500,000 bail.
“It’s something I’ll probably never know; what I know is that the person or entity who paid the bail wishes to remain anonymous,” she told swissinfo.ch.
Since leaving Iran, Shourd had heard the $500,000 might have been paid by an Iranian, while rumors say the Gulf sultanate of Oman may have settled the bill.
When asked about her detention, she said, “I was not tortured, I was kept in solitary confinement, complete solitary confinement for the first two months, then I was allowed a brief period of human contact every day with Shane and Josh.”
She said more about the circumstances surrounding her arrest.
“We were hiking on a very clearly marked trail, right behind that waterfall where lots of tourists visit and picnic in Iraqi Kurdistan, but we were near the border with Iran without us knowing about that because there’s no indication of a border there.”
Iran has accused Shourd and her two companions of deliberately crossing the border and spying.
Shroud denies accusations of spying and claims she was working as an English teacher to Iraqi and Palestinian refugees in Syria.
“If indeed we did cross into Iran, it was completely unintentional, but to this day, we’ve seen no convincing evidence we crossed the border intentionally,” she said.
Shourd describes herself and her two friends as “a peace activist.”
She adds that she met her fiancé while “organizing against the invasion and occupation of Afghanistan and Iraq.”
But despite everything she has been through, she says she is “more determined than ever to continue in that path”.
“We need people to be bridges between the West and the Middle East.”
Switzerland has represented Washington's interests in Iran since 1980. It also looks after Iranian interests in Egypt.
There were 184 Swiss expatriates, mostly dual nationals, based in Iran in 2008.
Swiss President Hans-Rudolf Merz met his Iranian counterpart Mahmoud Ahmadinejad in Geneva in April.
Micheline Calmy-Rey made a controversial visit to Teheran in 2008 to attend the signing of a gas deal between a Swiss energy company and the Iranian government.
Iran is one of Switzerland's most important trading partners in the Middle East.
Human rights dialogue with Iran
Switzerland has conducted a human rights dialogue with Iran since October 2003.
The Iranian partners are officials from the ministries of justice and foreign affairs.
The dialogue focuses on the death penalty, corporal punishment, torture, freedom of expression, the rights of minorities and of women.
So far there have been four official rounds of dialogue.
In 2004 Swiss experts were able to visit a number of prisons in Iran.
On September 12-13 a meeting of experts in Tehran compared and discussed the criminal law relating to young offenders in the two countries.
Swiss Foreign Minister Micheline Calmy-Rey has said that she always raises human rights issues when she meets Iranian leaders.
Human rights in Iran
There are tight restrictions on freedom of expression, association and assembly.
Civil society activists are liable to be arrested and prosecuted, often in unfair trials.
They are often banned from travelling abroad, and their meetings may be disrupted.
Torture and other ill-treatment of detainees are common, and goes unpunished.
Many detainees are denied medical attention.
Sentences include flogging and amputation.
At least 346 people are known to have been executed in 2009, but the number was probably higher.
Two men were executed by stoning.
Among those executed were eight juvenile offenders.
At least 133 faced execution for crimes committed while they were minors.
Source: Amnesty International Iran Country Report 2009
(Translated from French by Emily Wright), swissinfo.ch