Iran and the US renewed negotiations earlier this month to tackle their decades-long dispute over Tehran's nuclear program as the US builds up its military capability in the Middle East, fuelling fears of a wider war.
Iran has threatened to strike US bases in the Middle East if it is attacked by US forces.
"The last round of talks showed that US ideas regarding the scope and mechanism of sanctions relief differ from Iran's demands. Both sides need to reach a logical timetable for lifting sanctions," the official told Reuters on Sunday.
"This roadmap must be reasonable and based on mutual interests."
Iran's Foreign Minister Abbas Araqchi said on Friday that he expected to have a draft counterproposal ready within days, while US President Donald Trump said he was considering limited military strikes.
While rejecting a US demand for "zero enrichment" - a major sticking point in past negotiations - Tehran has signalled its readiness to compromise on its nuclear work.
Washington views enrichment inside Iran as a potential pathway to nuclear weapons. Iran denies seeking nuclear weapons and wants its right to enrich uranium to be recognised.
Washington has also demanded that Iran relinquish its stockpile of highly enriched uranium (HEU).
The UN nuclear agency last year estimated that stockpile at more than 440 kg of uranium enriched to up to 60 per cent fissile purity, a small step away from the 90 per cent that is considered weapons grade.
The Iranian official said Tehran could seriously consider a combination of exporting part of its HEU stockpile, diluting the purity of its most highly enriched uranium and the establishment of a regional enrichment consortium in exchange for the recognition of Iran's right to "peaceful nuclear enrichment".
"The negotiations continue and the possibility of reaching an interim agreement exists," he said.
Iranian authorities have said that a diplomatic solution delivers economic benefits for both Tehran and Washington.
"Within the economic package under negotiation, the United States has also been offered opportunities for serious investment and tangible economic interests in Iran's oil industry," the official said.
However, he said Tehran will not hand over control of its oil and mineral resources.
"Ultimately, the US can be an economic partner for Iran, nothing more. American companies can always participate as contractors in Iran's oil and gas fields."
