The reasons for Ahmad Nuri's arrest on Wednesday were not immediately clear, the correspondent said.
Many journalists in Iraq, including several Aljazeera reporters and cameramen, have been detained in the past by occupation troops or police and then released without charge or apology.
Iraqi journalists have been particularly vulnerable to detention by foreign occupation forces or the interim government.
Reporters covering the unrest in Iraq have come under renewed pressure in recent days.
On Tuesday, an Iraqi freelance journalist working for Germany's ZDF television was killed in Falluja.
Mahmud Hamid Abbas, 32, had gone to the city on Sunday to film, when he was killed "in unexplained circumstances," his employers said.
The media watchdog Reporters without Borders (RSF) said the journalist was killed as he was leaving his native Falluja for Baghdad.
There was no evidence he had been targeted by a missile, rocket or bomb fired by either Iraqi fighters or occupation troops. He might have been killed by criminals active in the area, said RSF.
Married with three children, Mahmud Hamid Abbas is the 20th journalist to be killed in Iraq this year and the 34th since the start of the fighting in March 2003, RSF said.
Elsewhere, a British freelance journalist was seized in Basra on Tuesday by an Iraqi group demanding that occupation troops should withdraw from Najaf. James Brandon was released after a few hours when aides of Shia leader Muqtada al-Sadr intervened.
As well as the risk of death and detention, reporters have faced other obstacles such as reporting restrictions imposed by the interim government.
Reporters covering the latest clashes in Najaf were ordered out of the city, in some cases at gun point, ostensibly "for their own safety".
And Aljazeera's bureau in Baghdad has been shutdown for a month after the US-appointed government accused the station of inciting opposition, a charge the network denies.