WASHINGTON (AP) -- The Obama administration is looking at new ways to pressure Iran over its nuclear program.

The State Department's nuclear negotiator with Iran, Wendy Sherman, and the Treasury Department's sanctions chief, David Cohen, are telling Congress that the U.S. is exploring different ways to press Tehran into making nuclear concessions.

These range from possible executive orders to military signals to U.S. efforts to end the civil war in Syria, a key Iranian ally.

Their comments came as the Treasury Department on Wednesday added two Dubai-based companies to an American blacklist of firms accused of supporting Iran's weapons proliferation activities.

The action bans Americans from doing business with Al Fida International General Trading or Al Hilal Exchange. Any assets held by those companies in the U.S. are now blocked.