Iranian Foreign Ministry spokesman Abbas Araqchi said on Thursday intensifying sanctions against Iran "makes the nuclear issue more complex and more difficult to resolve".
"It will not help a resolution to the nuclear issue, rather it would help Iran consolidate its nuclear rights," Fars news agency quoted him as saying.
Iran called the bill counterproductive and Turkey, an importer of Iranian oil, said it would struggle to cut imports any further after having already reduced them by 40 percent.
A Turkish official said further cuts "would greatly stretch Turkey". Turkey's refiner Tupras has already increased purchases from Saudi Arabia, Libya and Iraq.