The United States had a plan for an extensive cyberattack on Iran in case diplomatic attempts to curtail its nuclear program failed, The New York Times reported on Tuesday, citing a forthcoming documentary and military and intelligence officials.

Code-named Nitro Zeus, the plan was aimed at crippling Iran's air defenses, communications systems and key parts of its electrical power grid, but was put on hold after a nuclear deal was reached last year, it said.

The plan developed by the Pentagon was intended to assure US President Barack Obama that he had alternatives to war if Iran moved against the United States or its regional allies, and at one point involved thousands of US military and intelligence personnel, the report said.