Iran’s Foreign Minister Mohammad Javad Zarif told reporters on Wednesday night in Vienna that the nuclear negotiations cannot be wrapped up in the next few days.

He told reporters that the talks are proceeding on the topic of sanctions and the possibility of extending the deadline for reaching a comprehensive final agreement.

He added that there is a need for serious decision-making, especially on the side of the 5+1, and so far nothing has been decided.

Restrictions on uranium enrichment, the fate of the Fordo and Arak plants and the mechanism for eliminating sanctions reportedly remain points of contention in the talks.

Zarif said the Iranian delegation is prepared to continue negotiations until July 20 but there is no consensus regarding the timing of the negotiations among the 5+1, according to the Iranian foreign minister.

There is serious speculation that this round of talks will end this month and resume in September. John Kerry returned to the U.S. after direct meetings with Zarif to discuss the progress of the negotiations with the U.S. president.

Barack Obama struck a positive note when he spoke of the talks on Wednesday, saying they are considering the possibility of extending the deadline for the final resolution.

According to the interim deal reached by the parties in Geneva last November, the final deal was to be reached by July 20.