Under interrogation, and probable torture, after their arrest in Shiraz three months ago, the two men implicated 11 other Jews, religious leaders and teachers, who were accused last weekend of spying for the Israelis and Americans.
Israel denied that the 13 had anything to do with its intelligence agencies and asked Kofi Annan, the United Nations secretary-general, to secure their release. Martin Indyk, the US assistant secretary of state, said it was difficult to reconcile the arrests with the soft words of Iran's President Mohammed Khatami about improving relations with the West.
Tehran radio's English- language service said they were accused of spying for the "Zionist regime" and "world arrogance" - references to Israel and the US. The Iranian news agency and the Farsi-language Iranian press have not repeated the allegation of espionage, leaving some doubt over the official status of the charge.
The 13 come from the southern city of Shiraz and nearby Isfahan and one of the charges against those most recently arrested is that they gave lessons in Hebrew.
In 1997 Iran hanged two people accused of spying for Israel and Menashe Amir, an Israeli specialist on Iran, said that the 13 were "in real danger because of the struggle between the moderate and fundamentalist Islamic camps in Iran in the run-up to the Iranian election in 10 months' time".
The background to the arrests is the simmering conflict in Shiraz between the 6,000-strong Jewish community and the local security services. For centuries Shiraz was a winemaking centre that gave the world the Shiraz grape. Vineyards in the Shiraz region were grubbed up after the Islamic revolution in 1979, however.
Iran still permits Jews and other non-Muslims to make wine for their own use. Selling it to Muslims is a grave offence. Today Shiraz is a stronghold of militant Islam, and local Muslim prayer leaders have accused Jews of closing their shops on Saturday, the Jewish sabbath.
Jews in Iran are an officially tolerated minority with a member in the Iranian parliament. While Jewish schools are forbidden, Iranian schools provide Jewish religious studies. But half the 100,000 Jews left Iran in two years after 1979. Some 27,000 remain, mostly concentrated in Tehran, with Shiraz the second biggest community.
The Jewish community in Shiraz is assertive and the original arrests may have been sparked off by its refusal to close shops on Friday rather than Saturday. This extended into a struggle between radical and moderate Islamic forces, with the radicals seeing the arrests as a way of undermining President Khatami's opening to the West.
Jewish groups in the United States and Europe believe the best chance of securing the release of the 13 is through France, which has good relations with Iran.The Foreign Office in London said it was "very worried" by the arrests, but did not think they would halt the thaw in relations between Britain and Iran.Reuse content