The Iranian foreign minister says a group of Iranians abducted by rebels in Syria include a number of retired Revolutionary Guards and soldiers.
Ali Akbar Salehi said they no longer had any military role and that they had been in Damascus for a pilgrimage when they were seized on Saturday.
Fighting continues in Syria's biggest city, Aleppo, with an unconfirmed report that rebels have pulled back.
New evidence has emerged of heavy weapons use in the city.
The rebels who are holding the Iranians accuse them of carrying out reconnaissance on behalf of the Syrian army.
Iran has asked the UN and Turkey for help in securing their release.
"A number of the [hostages] are retired members of the Guards and the army," Mr Salehi was quoted as saying by the Iranian Students' News Agency as he flew back from Turkey.
"Some others were from other ministries."