WASHINGTON, Nov 24 (Reuters) - The U.S. Senate is likely to consider legislation that would threaten new sanctions on Iran if it does not comply with an interim nuclear deal but would also provide a six-month window before any of the actions would take effect, a key U.S. Democrat said on Sunday.

Senator Robert Menendez, who is chairman of the Senate Foreign Relations Committee, said in a statement that forthcoming legislation would "provide for a six-month window to reach a final agreement before imposing new sanctions on Iran."

But Menendez said the legislation would make clear that the sanctions would be available if the talks falter or if Iran fails to implement or breaches the interim agreement. (Reporting by Caren Bohan and Patricia Zengerle; Editing by Sandra Maler)