The American Secretary of State has said that “significant gaps” remain between Iran and world powers after the latest talks in Switzerland, aimed at securing a deal over Tehran’s nuclear programme.
John Kerry then flew to Saudi Arabia for talks with Gulf leaders.
Before leaving Montreux, he said some progress had been made in negotiations with his Iranian counterpart Mohammad Javad Zarif.
Talks are due to resume on March 15.
US aides say many obstacles remain before the deadline for reaching a framework agreement by the end of the month.
The Israeli prime minister’s warning to the US Congress against a deal has been strongly criticised in Iran.
One newspaper headline said “Netanyahu Makes a Fool of Himself Yet Again”.
The Iranian parliamentary speaker called his speech a “political show”.
Benjamin Netanyahu said what he called a ‘bad deal’ could spark a ‘nuclear nightmare’.
Kerry’s response was also a veiled rebuke to the Israeli leader.
Kerry said politics and external factors would not distract from the talks, which aim to constrain Iran with intrusive UN access and verification of its nuclear activity and lengthen the “break-out” time needed for it to build any nuclear weapon.
“No one has presented a more viable, lasting alternative for how you actually prevent Iran from getting a nuclear weapon. So folks, simply demanding that Iran capitulate is not a plan. And nor would any of our P5+1 partners support us in that position.”
The other P5+1 countries are Russia, China, France, Britain and Germany, who would all have to sign off on any deal.
On Tuesday Iran criticised as ‘unacceptable’ US President Barack Obama’s demand for Iran to freeze its sensitive nuclear activities for at least 10 years.