US Secretary of State John Kerry on Monday warned the Zionist prime minister against revealing details of an Iran nuclear deal that world powers are in the process of negotiating.

US Secretary of State John Kerry on Monday warned the Zionist prime minister Banjamin Netanyahu against revealing details at his upcoming speech to US Congress c

While he did not mention Netanyahu by name, Kerry told reporters in Geneva he was "concerned by reports" that "selective details" of the deal aimed at curbing Tehran's nuclear program would be revealed in the coming days.

His comments come after a Zionist official said the Jewish entity knew about the emerging agreement and that the PM would elaborate in his congressional address.

Kerry is due to meet his Iranian counterpart Mohammad Javad Zarif in the Swiss lakeside town of Montreux later Monday for talks on the Iran agreement.

"The best way to deal with the question surrounding this nuclear program is to find a comprehensive deal, but not a deal which comes at any costs," he told reporters.

"We have made some progress, but we still have a long way to go, and the clock is ticking."

The P5+1 group of world powers that are negotiating with Iran have until March 31 to reach a framework for a deal, which would then be firmed up and officially signed on June 30.