Iran is ready to resume nuclear enrichment "without any limitations" unless sanctions are totally and immediately removed at the end of negotiations, Foreign Minister Javad Zarif said.
Speaking to TV channel Euronews on Friday in Lisbon, Zarif said: "We can have the path of confrontation or we can have the path of co-operation, we cannot have a little bit of each."
"If we take the path of confrontation, the US and the UN will continue with their sanctions, and Iran will continue with its enrichment programme. Without any limitations," Zarif said.
"Unfortunately the United States started... using the phrase 'phased sanctions'," Zarif added.
"If you go through the joint statement you will not even see the word 'suspension' and you will not see the word 'phase'. It's clear that all sanctions, all economic and financial sanctions will be terminated."
Global powers reached a framework agreement for a nuclear deal with Iran on April 2.
They must now resolve a series of technical issues by a June 30 deadline for a final deal, including the steps for lifting sanctions on Iran, and remaining questions over the possible military dimensions of its nuclear programme.
Zarif told Euronews that there were discrepancies between the framework agreement and the "fact-sheet" released by the United States to explain what had been decided.
"On the day that we agree we will go to the Security Council and the Security Council will adopt a resolution which will terminate all the previous resolutions and will set the stage for termination of all sanctions. This is very clear, there won't be phased, there won't be suspensions, it is very clear in the agreement that we announced." he told Euronews.
He said negotiations were at times difficult because Western powers had "come to believe that sanctions were an asset, were something that they should not relinquish so easily".
"Now we start the difficult part, the difficult path of negotiating and writing the final agreement," said Zarif.