The Iranian Foreign Ministry said that an agreement can be reached before the end of this month, and that the matter is related to the other side's response to the Iranian proposals presented in the current negotiations in Vienna, while talks are continuing in parallel between Tehran and Washington regarding the exchange of prisoners.
Iranian Foreign Ministry spokesman Saeed Khatibzadeh said - in a press conference in Tehran - that they are seeking to obtain real guarantees from Washington to prevent it from violating the agreement again.
Zadeh reiterated Iran's demand for the United States to lift all sanctions stipulated in the nuclear deal.
He added that the ongoing nuclear talks in Vienna had not reached a dead end, and that the main issues that needed political decisions were under discussion in Vienna.
He stressed that Tehran had already made its political decision to remain in the 2015 nuclear agreement after Washington withdrew from it in 2018.
On Sunday, Iranian media quoted a source - whom it described as close to the Vienna negotiations - that the United States has not yet taken a decision regarding the Vienna talks, accusing Washington of procrastinating.
The Iranian news agency (IRNA) quoted this source as saying that a large part of the texts of the agreement have been drafted, which is a remarkable progress in the negotiations.
The source added that if Western countries take the necessary decisions regarding lifting sanctions and nuclear files, a "result" can be reached in a very short period of time.
On Sunday, the Russian delegate to international organizations in Vienna, Mikhail Ulyanov, spoke in a tweet on Twitter about making tangible progress in the ongoing negotiations in the Austrian capital.
The eighth round of the Vienna negotiations between Iran and the 4+1 group began on the seventh of this month, interspersed with statements by the participating parties that the negotiations had entered their final and decisive stages, and Washington's repeated demands to expedite an agreement.
The current negotiations aim to allow Washington and Tehran to simultaneously return to abide by the agreement supported by current US President Joe Biden.
Tehran demands the lifting of all sanctions targeting it, and says that it has returned a clear program of action to Vienna, while the United States considers that the conclusion of the agreement has become an urgent matter.
Regarding the prisoner exchange talks, the Iranian Foreign Ministry spokesman said that the talks with Washington are continuing, parallel to and independent of the Vienna talks, adding that they are taking place through mediators and indirect channels.
He explained that this issue is currently on the agenda in parallel with the Vienna talks, but it seems that the United States has not taken a decision on it, perhaps waiting for the results of the talks.