Talks are underway in Geneva, Switzerland, to help end the decades-old standoff over Iran's nuclear program.
Iranian officials say they're serious about negotiating. They delivered what they're calling a potential breakthrough to the U.S. and five other world powers.
The talks are seen as the biggest chance in years to resolve disagreements over the country's nuclear ambitions.
Israel's prime minister is urging negotiators not to give in until Iran gives up its nuclear plans.
"I think it would be a historic mistake to ease the sanctions when they're so close to achieving their goals," said Benjamin Netanyahu.
The countries aren't expected to reach a final deal in the two-day session. However, Iranian officials say they're ready to build a path of trust with the West.