A top Iranian opposition leader is telling Congress that Iranians call the government in Tehran the "godfather" of the Islamic State militant group and says the regime wants nuclear weapons to keep supporting rising Islamic extremism.

Maryam Rajavi (MARE-ee-am rah-JAH-vee) says provisions of an emerging nuclear deal are not tough enough and says giving concessions to Iran will embolden it to become more aggressive.

Rajavi is president-elect of the Paris-based National Council of Resistance of Iran. She testified Wednesday before a House Foreign Affairs Committee subcommittee, via videoconference from France. She is the first member of the resistance groups to testify before Congress.

She says Iran must completely stop enriching uranium and shut down its nuclear sites, missile programs and other programs.