Iran is to put on trial three Americans accused of spying in a move that is sure to strain already frayed US-Iranian relations.
Iran's foreign minister, Manouchehr Mottaki, told a press conference that the three hikers would face the judiciary after they were arrested for crossing the border from Iraq in July.
"They have entered Iran with suspicious aims. They will be tried by Iran's judiciary and verdicts will be issued," Mottaki said.
He did not give a date or details of the charges. Shane Bauer, 27, Sarah Shourd, 31, and Josh Fattal, 27, were accused of espionage last month.
Their relatives and the US government say the three were innocent tourists trekking in northern Iraq and accidentally crossed into Iran, where they were arrested on 31 July.
Iran had threatened to charge five British yachtsmen who strayed into Iranian waters last month. But an international crisis was averted when Iran freed the crew after holding them for just over a week.
The fate of the Americans appears more serious. They have been held for more than four months, but the foreign minister's comments are the first clear indication that Iran plans to put them on trial.
When they were accused of spying the US secretary of state, Hillary Clinton, said: "We believe strongly that there is no evidence to support any charge whatsoever."
The Iranian president, Mahmoud Ahmadinejad, has suggested his regime will use the fate of the Americans as a diplomatic lever in Tehran's increasing tense standoff with the west over its nuclear programme.
"We don't like to see anybody going to jail, but after all, there are some violations and judges have the right to make a decision. Hopefully all these problems would be resolved," he told a press conference last month.
Ahmadinejad linked the plight of the three Americans with cases of Iranians detained by the US, including Amir Hossein Ardebili, who pleaded guilty to plotting to pass on US military technology to Iran.