Foreign Minister Kamal Kharrazi has announced that 12 suspected al-Qaeda members being held in Iran will go on trial but he did not say when.
Al-Qaeda spokesman Sulaiman Abu Ghaith is alleged to be in Iran
Mr Kharrazi told reporters in Davos that the identities of those to be tried had not been announced.
In June last year, Iran said it was holding several al-Qaeda members, some of whom were said to be senior figures.
A White House spokesman said Iran had ignored requests to hand over the suspects to their countries of origin.
US officials have long alleged that some of al-Qaeda's more senior members have sought sanctuary in Iran and have repeatedly accused Tehran of harbouring them.
Iran has strenuously denied such allegations, although it admits that some may have slipped across its borders.
US officials have also said they believe the suicide bombings in the Saudi capital Riyadh in May of last year were planned by al-Qaeda operatives in Iran - a charge also denied by Tehran.
Mr Kharrazi, who is attending the World Economic Forum in the Swiss resort of Davos, said about a dozen al-Qaeda suspects were currently in prison.
"Their relations are cut off from outside and they are going to be tried," he told Reuters news agency.
Reacting to Mr Kharrazi's comments, White House spokesman Scott McClellan said: "We want to see action, and the action we want to see is that they turn over those al-Qaeda members in their custody to their country of origin."
Among those possibly in Iranian detention are al-Qaeda spokesman Sulaiman Abu Ghaith and Osama Bin Laden's son, Saad Bin Laden, Saudi sources reported last year.
Osama Bin Laden's security chief Saif al-Adel, sometimes regarded as al-Qaeda's current number three leader and alleged to have trained some of the 11 September hijackers, is also said to be in the country.