Sarah Shourd, a U.S. woman released Tuesday from a yearlong detention in Iran, says she is grateful to Iranian authorities for letting her go and singles out Iranian President Mahmoud Ahmedinejad for his compassion..

Sarah Shourd is seen at a hotel in Tehran in May 2010, when authorities allowed a visit with her mother. On Tuesday, Shourd was released after more than a year in prison. (Press TV/Associated Press)

Shourd, 32, flew to Oman from Tehran to meet her mother after bail of $500,000 US was posted. It is not clear who paid the bail.

"I want to really offer my thanks to everyone in the world, all of the governments, all of the people, that have been involved, and especially, particularly want to address President Ahmadinejad and all of the Iranian officials, the religious leaders, and thank them for this humanitarian gesture," Shourd told Iran's English-language Press TV at the airport before she flew out.

Shortly after her departure, U.S. President Barack Obama welcomed Shourd's release and said he remains hopeful that the Tehran government will release two other Americans.

"I am very pleased that Sarah Shourd has been released by the Iranian government, and will soon be united with her family," Obama said in a statement. "All Americans join with her courageous mother and family in celebrating her long-awaited return home."

Shourd arrived in Oman after a flight of about two hours. She was greeted with an embrace from her mother. Looking relaxed and smiling, they strolled arm-in-arm.

Shourd was one of three Americans arrested after crossing into Iran on July 31, 2009. Two men, Shane Bauer and Josh Fattal, remain in custody, and the Iranian judiciary said their detention would be extended by another two months.

The three were accused of illegally crossing the border and espionage. They had been hiking in the mountains of Kurdistan, which span the border between Iraq and Iran.

Health problems

Their families say the three — graduates of the University of California, Berkeley — accidentally strayed over an unmarked border.

In this May 20, 2010, file photo, American hikers Shane Bauer, left, Sarah Shourd, centre, and Josh Fattal sit at the Esteghlal Hotel in Tehran. (Press TV/Associated Press)

Obama said Bauer and Fattal committed no crime, and he remains hopeful that Iran "will demonstrate renewed compassion by ensuring the return of Shane, Josh and all the other missing or detained Americans in Iran."

On Saturday, Iran's judiciary granted Shourd's release on bail of $500,000 US for health reasons. However, her family said they could not afford the price, and the United States declined to pay it.

Shourd's mother had said her daughter is suffering from health problems, including a breast lump and precancerous cervical cells.

Ahmadinejad personally intervened to get Shourd released as an act of clemency at the end of the Muslim holy month of Ramadan, according to state media.

However, the judiciary blocked plans to let her go just hours before a planned release on Saturday.

Tehran's chief prosecutor, Abbas Jafari Dowlatabadi, said a $500,000 bail had been paid to Iran's Bank Melli in Muscat, Oman, but did not say who paid it.

U.S. State Department spokesman P.J. Crowley said he could not say whether any money had changed hands in winning Shourd's release, but noted that "arrangements were made that satisfied Iranian requirements under their judicial system."

At the same time, he said the U.S. government had no information to suggest that any U.S. or international sanctions imposed on Iran over its nuclear program had been violated in making those arrangements.

With files from The Associated Press