Secretary of State John Kerry said a deal on Iran's nuclear weapons program could be reached relatively quickly, and it would have the potential to dramatically improve the relationship between the two countries, Reuters reported.
Kerry said intensifying 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," Kerry said in an interview aired on CBS's "60 Minutes" on Sunday.
"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," he said.
Rouhani and U.S. President Barack Obama spoke by telephone on Friday in the highest-level contact between the two countries in three decades, raising hopes of a breakthrough in Western efforts to prevent Iran from building a nuclear bomb.
The call was the culmination of a recent, dramatic shift in tone between Iran and the United States, which cut diplomatic relations a year after the 1979 Iranian revolution.
Kerry said Iran could prove its sincerity by immediately opening its nuclear facilities to inspections and keeping its uranium enrichment efforts at lower grades that were not suitable for military use.
Iran has defended its right to enrich uranium as part of a civilian nuclear energy and medicine program and denied that it aims to develop atomic weapons, but the United States and its allies have sought an end to higher-grade uranium enrichment that could be a step away from the production of weapons-grade material.
"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 said.
"Words are not going to replace actions," he said. "What we need are actions that prove that we and our allies, our friends in the region, can never be threatened by this program."
In a separate interview, Iran's foreign minister said the country's right to peaceful nuclear enrichment was not negotiable but it did not need to enrich uranium to military-grade levels.