Josh Fattal and Shane Bauer were arrested along with Sarah Shourd near the border with Iraq in July, 2009 [Reuters]

Two US hikers freed by Iran after being held for more than two years on accusations of spying have returned to the US, ending a diplomatic ordeal that began with what they called a wrong turn into the wrong country.

The two were freed on Wednesday after the Gulf sultanate of Oman paid $1m bail for their release from Tehran's  Evin prison.

Shane Bauer and Josh Fattal, both 29, were arrested with Bauer's fiancee Sarah Shourd near the mountainous border with Iraq on July 31, 2009.

Throughout the ordeal they consistently maintained they innocently strayed into Iran while hiking in northern Iraq's Kurdistan region, but an Iranian court last month convicted Bauer and Fattal to eight years in prison for spying.

Shourd was released last year on $500,000 bail, also paid by Oman. Since her release last year, Shourd has lived in Oakland, California.

Bauer and Fattal were released on September 21 and first went to Oman to meet Qaboos Bin Said, the country's sultan, as well as the US ambassador in the Gulf state.

Chavez role

Mahmoud Ahmadinejad, Iran's president, agreed to their release last week as the UN General Assembly gathered in New York, saying it was a humanitarian gesture.

Iran's foreign ministry called their release a gesture of Islamic mercy.

Hugo Chavez, Venezuela's president, who has maintained a strong relationship with Iran, was reportedly involved in negotiating the hikers' release.

Temir Porras, Venezuela's deputy foreign minister, told the Reuters news agency the Venezuelan president took up the case with the government of ally President Ahmadinejad after being alerted to the Americans' plight by friends in US intellectual circles.

An unnamed source "close to the release process" told Reuters that the US state department had been aware of Chavez's involvement in the attempts to free the hikers and did not try to block it.

On Thursday, a state department spokesperson said they were happy Fattal and Bauer were safe.

"He talks regularly with President Ahmadinejad. On the occasions he could, he requested it as a humanitarian, brotherly gesture," Porras said.

"They (Fattal and Bauer) were in an unfortunate situation, wrapped up in geopolitical tensions that went beyond them."