US President Barack Obama on Thursday called the release of American hiker Sarah Shourd from Iran a "bittersweet" moment, as he urged the release of her two companions still held in Tehran.
Obama earlier met with Shourd, 32, who was set free two weeks ago after spending more than a year behind bars in Iran, but had to leave behind her fiance Shane Bauer and friend Josh Fattal.
Shourd was accompanied at the White House meeting by her mother, Norah, Bauer's mother Cindy Hickey, Fattal's mother Laura and his brother Alex.
"We share in the joy of Sarah's family, friends and all Americans who have lent their support, prayers and hope throughout this horrific ordeal," the White House said in a statement.
"In a meeting with Sarah and the mothers of the three hikers who were detained by the Iranian government, the president noted that this occasion remains bittersweet," it added in a reminder that Bauer and Fattal are still behind bars.
The hikers say they accidentally strayed into Iran in July 2009 while hiking in the mountains of Iraqi Kurdistan. But Iranian authorities claim they were spies.
"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," the White House said.
"We continue to salute the courage and strength of the Shourd, Bauer and Fattal families, who have endured the unimaginable absence of their loved ones."
It said Obama stressed the United States would "continue to do everything we can to secure the release of Shane and Josh."
Oman mediated the release earlier this month of 32-year-old Shourd, and US officials have said an Omani delegation is in Iran this week to seek the release of her two companions.
Shourd was freed after bail of around 500,000 dollars was paid. She met with hardline Iranian President Mahmoud Ahmadinejad last week in New York, where he was on travel to attend the UN General Assembly, to plead for the two men's case.