"Iraqi security forces have launched a wide campaign in Sunni Muslim-dominated neighborhoods of Baghdad and towns and cities to the north and west of the capital.
The campaign is said to be the widest by the government in years and has led to an exodus of people to the Kurdish north.
The campaign comes as the country gears for national elections in March.
The summary arrests have fuelled anger in these areas and raised fears of popular unrest at a time the government finds it extremely hard to reinstate law and order.
In Baghdad most of the arrests have taken place in the restive township of Abu Ghraib, home to the notorious Iraqi prison bearing the same name.
Parents and relatives said they have no idea where the security forces are keeping their beloved ones. They said officials told them all those arrested will remain behind bars until after the elections.
Officials speaking on condition of anonymity said hundreds of young people have been taken away from Tikrit, Anbar and Mosul.
They said popular discontent was apparent in the restive city of Mosul where rebels fighting U.S. and government troops are quite active."