Speaking with ICANA on Wednesday, Behrouz Kamalvandi added that Iran would strictly stick to its schedule.
"Nuclear commitments are being suspended as per the Iranian government's Reciprocal and Proportional Action for Implementing JCPOA Act passed by the parliament", using the abbreviation for the formal name of the nuclear deal—the Joint Comprehensive Plan of Action.
The nuclear deal was signed between Iran and six world powers in 2015, but the United States pulled out last year and restored sanctions, Financial Tribune reported.
Other parties remained in the accord and pledged to safeguard Tehran's interests, with Europe taking the lead by devising a financial mechanism to keep trade with Iran afloat, although it has not been activated yet.
As they failed to deliver on their promises, Iran stopped its compliance with two of its obligations under JCPOA in early May and vowed to further reduce its commitments if the remaining signatories fail to take practical steps to shield it against American sanctions within 60 days.
On Monday, Iran reiterated that it would surpass the uranium stockpile limit set by the deal in 10 days.
"Their [JCPOA parties'] behavior indicates that they don't want to meet their obligations or are unable to, in which case we have become certain [about our next move]," Kamalvandi said.
He added that Iran's reaction will depend on other parties' measures.
"For Iran to pull back from its suspension plan, the 4+1 [France, Britain, China, Russia and Germany] need to fulfill their duty," he said.
Kamalvandi noted that if they uphold Iran's rights under JCPOA, with the lifting of sanctions, Iran would meet its commitments, otherwise it would reduce its compliance.
"We are creating a balance between our commitments and our rights," he said.
In a Cabinet meeting on Wednesday, President Hassan Rouhani also said if JCPOA parties meet their duties in the remaining time, "all measures taken within the first 60 days as well as those potentially taken during the second 60 days will be reversed".