Iranian President Hassan Rouhani demanded on Sunday that Barack Obama block an extension of sanctions passed by the U.S. Congress, saying Tehran would otherwise “firmly respond”.

In a speech to parliament, Rouhani denounced legislation passed by the U.S. Congress to extend the Iran Sanctions Act (ISA) for 10 years as a violation of Tehran’s nuclear deal with six major powers. The deal curbs Tehran’s nuclear program in return for the lifting of international financial sanctions.

“America’s president is obliged to exercise his authority by preventing its approval and particularly its implementation … and if this gross violation is carried out we will firmly respond,” Rouhani said in the speech, carried live by state television.

President Obama is expected to sign the legislation into law, the White House said on Friday.