A European Union Council source said 15-20 Iranian officials and organizations have been added to the list.
The source said the EU has suggested that Iran and the EU take simultaneous action - Iran should stop its enrichment activities and the EU should lift its sanctions against Iran.
Since Iran resumed uranium enrichment in January 2006, the country has been the focus of international concerns, as some Western countries, particularly the U.S., suspect Tehran is pursuing a covert weapons program.
However, Tehran has consistently claimed it needs nuclear power for civilian power generation and is fully entitled to its own nuclear program.
The UN Security Council passed a new resolution on Iran March 24 over its refusal to abandon its nuclear program, toughening economic sanctions against the country and accepting the possibility of a military solution to the crisis.
But in defiance to international efforts, Iran announced in April it had started production of nuclear fuel on an industrial scale, and voiced its determination to defend a legitimate right to possess nuclear power.
High-ranking Iranian officials, including President Ahmadinejad, have repeatedly stated that Iran would not discuss shutting down its uranium enrichment program even if discussions with five permanent members of the UN Security Council and Germany are resumed.
