The White House is condemning what it calls an "organized intimidation campaign" by the Iranian government against opposition leaders and other activists.
In a statement released Sunday, National Security Council spokesman Tommy Vietor accused Iran of "blatant violation of the universal rights of its citizens."
An international human rights group said Sunday that Iranian security forces had abducted two opposition leaders and their wives.
Vietor said Tehran's intimidation campaign included "arrests of political figures, human rights defenders, political activists, student leaders, journalists and bloggers," as well as jamming satellite transmissions and blocking Internet traffic.
The spokesman called for Iranian leaders to "allow active dialogue among its citizens, freedom of speech and freedom of assembly without fear."