John Kerry, Jen Psaki at right
John Kerry, Jen Psaki at rightReuters

A deal on Iran's nuclear weapons program could be reached quickly and would have the potential to dramatically improve the relationship between Iran and the United States, Secretary of State John Kerry said on Sunday.

Speaking to CBS’s “60 Minutes”, Kerry predicted that diplomatic efforts to resolve the dispute over Iran's nuclear program could produce an agreement within the three to six month time frame that Iranian President Hassan Rouhani has called for.

"It's possible to have a deal sooner than that depending on how forthcoming and clear Iran is prepared to be," he said, adding, "If it is a peaceful program, and we can all see that - the whole world sees that - the relationship with Iran can change dramatically for the better and it can change fast.”

Kerry told the program that Iran could prove its sincerity by immediately opening its nuclear facilities to inspections and keeping its uranium enrichment efforts at lower grades that are not suitable for military use.

"Iran needs to take rapid steps, clear and convincing steps, to live up to the international community's requirements regarding nuclear programs, peaceful nuclear programs," Kerry told “60 Minutes”.

"Words are not going to replace actions," he stressed. "What we need are actions that prove that we and our allies, our friends in the region, can never be threatened by this program."

Kerry added that the sanctions on Iran could be lifted after an agreement was in place that ensured Iran's nuclear program was peaceful.

"The United States is not going to lift the sanctions until it is clear that a very verifiable, accountable, transparent process is in place, whereby we know exactly what Iran is going to be doing with its program," he told the program.

Since Rouhani, who has been branded a moderate by the West, was elected president, he has called for "constructive interaction" with the world, a dramatic shift in tone from the anti-Western and anti-Israeli rhetoric of his predecessor, Mahmoud Ahmadinejad.

Rouhani recently said that the time for resolving Iran's nuclear dispute with the West was limited, urging the world to seize the opportunity of his election. At the same time, he has stressed that Tehran would not consider halting the country’s uranium enrichment activities entirely.

Rouhani has exchanged letters with U.S. President Barack Obama, who wrote to him that the United States is ready to resolve its nuclear dispute with Iran in a way that allows Tehran to show it is not trying to build weapons.

In his speech to the General Assembly on Tuesday, Obama reached out to Iran, reiterating American opposition to the idea of Iran obtaining a nuclear weapon but supporting an Iranian civilian nuclear program.