[caption id="attachment_149211" align="alignright" width="216"] Iranian Foreign Minister Mohammad Javad Zarif[/caption]

(Bloomberg) -- Iran’s Foreign Minister Mohammad Javad Zarif signaled that talks over his country’s nuclear program are unlikely to reach an agreement this week, even as the two sides said unmistakable progress had been made.

Negotiators have given themselves until March 31 to agree on a framework agreement.

Attending the latest round of talks in Lausanne, Switzerland are Zarif, U.S. Secretary of State John Kerry, and other officials. They probably won’t be joined at this stage by other ministers from China, France, Germany and Russia -- arrivals that could indicate a final agreement is close.

“Anytime solutions are found and we are reaching an agreement then perhaps is the time for the Foreign Ministers,” Zarif said. “Now I don’t think is the time.”

Envoys negotiating the accord said Tuesday they’ve narrowed their disputes and that the participation of top scientists, including U.S. Secretary of Energy Ernest Moniz and Ali Akbar Salehi, head of Iran’s Atomic Energy Organization, have bridged technical gaps.

This week’s talks are set to last until at least March 20. After meetings next week in Washington, Kerry could resume negotiations around March 25, said a U.S. official, speaking on the condition of anonymity.

I “doubt if we can get there in next two days,” Zarif said.

By Swissinfo