The Omani official gave no further details on any possible timetable for the release of Shane Bauer and Josh Fattal who were detained along the Iran-Iraq border in July 2009 with their friend, Sarah Shourd. The Omani official spoke on condition of anonymity because of the sensitivities of negotiations.
The Omani intervention suggested movement on the complicated judicial and diplomatic dealings over the total $1 million bail, which was thrown into doubt earlier Wednesday when Iran's judiciary said the deal still needed review.
A plane sent by Oman's sultan brought Shourd from Iran last September after payment of $500,000 bail. Oman has close ties with both Tehran and Washington, and plays a strategic role in the region by sharing control with Iran of the Strait of Hormouz at the mouth of the Gulf, which is the route for 40 percent of the world's oil tanker traffic.
The Americans' defense attorney, Masoud Shafiei, told The Associated Press he is moving ahead with the bail arrangements with Swiss Embassy officials, who represent U.S. interests in Iran because there are no diplomatic relations between the two countries. There were no details given on the source of the money.
"I have informed both the hikers' families and the Swiss embassy, which represents the U.S. interests, and as soon as the bail is prepared, we will deposit and God willing, they will be released," he said.
Earlier Wednesday, Iran's powerful judiciary clouded the case by saying it was still reviewing the bail provisions. It was a potentially embarrassing rejection of President Mahmoud Ahmadinejad's prediction that their release could come in a matter of days.
The statement by the hard-line judiciary appeared to be a message that only its officials can set the timetables and conditions on any possible release and not the president, who is locked in a bitter power struggle with Iran's ruling clerics who control the courts.
It also could be a swipe at Ahmadinejad's hopes of timing the release of Shane Bauer and Josh Fattal with his expected arrival in New York next week for the U.N. General Assembly.
On Tuesday, defense lawyer Shafiei said the court handling the case set bail of $500,000 each for the Americans. Shourd was released last year on the same bail - but only after similar mixed messages between Ahmadinejad and the judiciary over the timing.
In the end, Shourd left Iran on an Omani jet just as Ahmadinejad was heading for New York.
The judiciary statement suggests that the bail plan for Bauer and Fattal still needs to be approved by the higher ranks of Iran's legal system, including members of the theocracy's inner circle.
"Two American citizens charged with espionage have not been released. Request from lawyers of these two defendants to issue bail and free (them) is under study," the state-run Islamic Republic News Agency quoted the statement as saying.
"Information about this case will be provided by the judiciary. Any information supplied by individuals about this is not authoritative," the statement added in a clear jab at Ahmadinejad.
Bauer and Fattal, both 29, were sentenced last month to three years each for illegal entry into Iran and five years each for spying for the United States. They have denied the charges and appealed the verdicts. Shourd's case remains open.
The Americans say they may have mistakenly crossed into Iran when they stepped off a dirt road while hiking near a waterfall in the semiautonomous Kurdish region of northern Iraq.
The U.S. government has appealed for the two men to be released, insisting that they have done nothing wrong. The two countries have no direct diplomatic relations and Washington relies on the Swiss Embassy in Tehran to follow the case.
Ahmadinejad, in an interview aired Tuesday on NBC's "Today" show, predicted the Americans could be freed "in a couple of days." He described the bail offer as a "humanitarian gesture" and repeated complaints about attention for Iranians held in U.S. prisons.
In Washington, Secretary of State Hillary Rodham Clinton said the United States was "encouraged" by Ahmadinejad's comments about freeing Bauer and Fattal.
The families of Bauer and Fattal said in a statement that they are "overjoyed" by the reports from Iran.
The possible release of the two Americans would remove one point of tension between Iran and the United States, but suspicions still exist on both sides and no thaw is in sight.
Washington and European allies worry Iran is using its civilian nuclear program as cover to develop atomic weapons and have urged for even stronger sanctions to pressure Tehran. Iran denies any efforts to make nuclear weapons.
Iran, meanwhile, is deeply concerned about the U.S. military on its borders in Iraq and Afghanistan, and sharply denounces U.S. influence in the Middle East.
The families of Bauer and Fattal said in their statement that their freedom "means more to us than anything and it's a huge relief to read that they are going to be released."
"We're grateful to everyone who has supported us and looking forward to our reunion with Shane and Josh," it added. "We hope to say more when they are finally back in our arms."
Shourd lives in Oakland, California; Bauer, a freelance journalist, grew up in Onamia, Minnesota; and Fattal, an environmental activist, is from suburban Philadelphia. Bauer proposed marriage to Shroud while in prison.
The last direct contact family members had with Bauer and Fattal was in May 2010 when their mothers were permitted a short visit in Tehran.
Their case closely parallels that of freelance journalist Roxana Saberi, an Iranian-American who convicted of spying before being released in May 2009. Saberi was sentenced to eight years in prison, but an appeals court reduced that to a two-year suspended sentence and let her return to the U.S.
At the time, a spokesman for the Iranian judiciary said the court ordered the reduction as a gesture of "Islamic mercy" because Saberi had cooperated with authorities and expressed regret.
In May 2009, a French academic, Clotilde Reiss, also was freed after her 10-year sentence on espionage-related charges was commuted.
Last year, Iran freed an Iranian-American businessman, Reza Taghavi, who was held for 29 months for alleged links to a bombing in the southern city of Shiraz, which killed 14 people. Taghavi denied any role in the attack.
El-Nahdy reported from Muscat, Oman. Associated Press writers Patrick Walters in Philadelphia, Jeff Baenen in Minneapolis and Matthew Lee in Washington contributed to this report.