The 13 will also get a few extra days to prepare their case, according to Malcolm Hoenlein, executive vice chairman of the Conference of Presidents of Major American Jewish Organizations.
Previously, the "Iran 13" -- who could be sentenced to death -- had been represented by lawyers appointed by the Islamic fundamentalist-controlled judiciary. The trial had been scheduled for April 13, but now will likely be held April 18, Hoenlein said Wednesday.
Yet despite the Iranian concessions, Hoenlein said, American Jewish organizations will go ahead with a flurry of high-profile activities aimed at both highlighting the plight of the prisoners and pressuring Tehran to end the entire yearlong ordeal.
"Our goal is their freedom, not just a solution to the lawyer question," Hoenlein said.
Iranian officials have indicated that the trial will be a one-day affair. If that's the case, the Jewish advocates will press Iran to release the prisoners on bail, regardless of the verdict, so they can return to their homes for Passover, which begins the evening of April 19.
It's unclear what prompted Tehran's change of mind.
Aside from the international outcry the arrests have provoked, some in the United States suspect that Iran did not want the trial to coincide with the beginning of the Islamic month of Moharram. The month commemorates the martyrdom of the prophets Hossein and Hassan.
Some Shi'ites, to express their grief, take to the streets with chains, knives and machetes, publicly inflicting harm on themselves. Out of respect, Iranian Jews and Christians generally stay indoors. Observers suggest the government may have found it in its best interests not to inflame passions on the streets with the trial of alleged "Zionist spies."
Both Israel and the United States vehemently deny the charges against the Iranian Jews, most of them communal or religious leaders from the southern cities of Shiraz and Isfahan.
Now, even with their own lawyers, the prospects for a fair trial seem more remote than ever. The hard-line clerics who control Iran's courts appear likely to renege on earlier promises to permit media and foreign observers to monitor the court proceedings.
Until now, U.S. advocates have pursued quiet diplomacy, marshaling support from many governments and human rights groups to release the detainees -- or at least to ensure a fair trial.
But having seen little progress, the advocates are now taking a more high-profile approach.
On the diplomatic front, Hoenlein said he expects the U.S. Congress to pass a bipartisan resolution that will denounce Iran for its detention of the Jews.
Governments around the world are being asked to pass similar resolutions, he added, while various leaders -- including some from Arab and Muslim countries -- have indicated they will step up efforts to pressure Tehran.
At the grass-roots level, vigils, but not street demonstrations, are being planned at various locations in the United States, said Hoenlein,.
Nationwide, rabbis across the religious spectrum have agreed to recite special prayers this weekend. In Los Angeles, the Council of Iranian American Jewish Organizations will hold a special commemoration on Sunday to mark the one-year anniversary of the arrests of 10 of the Iran 13.
Sam Kermanian, secretary general of the Iranian American Jewish Federation, chastised the Iranian government. "None of the aspects of this case are being handled in accordance with Iranian law, let alone international standards," he said. "This is not an issue we can compromise on." On Wednesday, Kermanian joined officials at The Jewish Federation of Greater Los Angeles in urging Jews around the world to offer a misheberakh, or blessing of healing, for the imprisoned Jews as they go to trial.
The Jews were reportedly arrested along with eight Muslim men. But none of the 21 has been formally charged, which also violates Iranian law, says Pooya Dayanim, the council's spokesman and himself a lawyer.
"Basically, these Jews are hostages," said Dayanim. "Iran may feel the longer it delays the trial, the less it will be internationalized and hurt them. Our job is to remind them that the world community still cares about these people."
The Jews are all community or religious leaders -- except for a 16-year- old boy who is one of three now out on bail.
Their arrest was believed to be part of a political battle between Iran's hard-line revolutionaries and reformists behind Iranian President Mohammad Khatami.
American observers had hoped that the resounding victory of Iran's reformists in the Feb. 18 parliamentary elections would bode well for the Jewish prisoners.
If anything, however, their situation has worsened, said Hoenlein.
"All the things we'd been promised and thought would come true, just the opposite has happened," he said.
"The mythology of Khatami being a reformer is just that -- mythology. So far, he has not shown himself to be any different from the others. If he's in control, the buck stops with him and he's responsible for this situation. If he's not in control, why are we dealing with him and making concessions?"