Hundreds of people have been detained since street protests broke out in the aftermath of presidential elections last year that opposition supporters say were rigged, an allegation that the government of President Mahmoud Ahmadinejad rejects.
Kaleme, the website of defeated candidate Mirhossein Mousavi, said nine journalists and photojournalists had been arrested in the past two days, taking the total to 55.
Those recently detained included Akbar Montajabi, assistant editor-in-chief of the magazine "Iran Dokht", which is close to Medhi Karroubi, another defeated candidate.
Parleman News, the website of parliament's minority reformist minority, said a female journalist had been arrested on Sunday. She was not among those named by Kaleme and it was not clear if she was among the 55.
Iran marks the anniversary of the 1979 Islamic revolution on Thursday, offering a potential cue for more violent protests.
Eight people were killed in clashes between security forces and opposition supporters on Dec. 27, the most serious violence since the aftermath of the June 12 election.
(Reporting by Reza Derakhshi; Editing by Kevin Liffey)
