The semiofficial Fars news agency quoted Tehran General Prosecutor Abbas Jafari Dolatabadi as saying the German national was released late on January 8 while the Syrian journalist will be freed later today.
Eight people were killed in clashes between security forces and supporters of opposition leader Mir Hossein Musavi on Ashura, a day of ritual Shi'ite mourning that fell on December 27.
It was the worst violence since protests in the immediate aftermath of a disputed presidential election in June. Opposition protesters say the vote was rigged in favor of President Mahmud Ahmadinejad, which the government denies.
The opposition website Rahesabz said on January 6 that more than 180 people, including 17 journalists, 10 Musavi aides, and some members of the outlawed Baha'i faith, were arrested in the aftermath of the December 27 protests.
A European diplomat was held for 24 hours.
Dolatabadi said that an unspecified number of Baha'is, whose faith is outlawed in Iran, will face trial this week. He did not give details.
"The German national was released last night and the Syrian reporter of Dubai Television will be released today," he said. He did not give any further information.
"The trial session of these Baha'is will be held during the current week at branch 28 of the Tehran Islamic revolutionary court," he added.
Dolatabadi said on January 8 that another five detainees Iran plans to try in connection with the antigovernment protests were members of the People's Mujahideen Organization of Iran (PMOI), an exile group opposed to Iran's Islamic system of government.