Iranian Foreign Minister Mohammad Javad Zarif said Tuesday extending nuclear negotiations with the P5+1 group beyond July 20 was possible.
"I have proposed the continuation of negotiations beyond the July 20 deadline," Zarif told reporters in Vienna.
He said he believed that US Secretary of State John Kerry and the rest of the P5+1 group would favor the extension of negotiations in a drive to reach a comprehensive agreement over the Iranian nuclear program.
Kerry had earlier in the day expressed optimism that an agreement on Iran's nuclear ambitions might be in the offing by perhaps next Sunday.
"I am returning to Washington today to consult with President Obama and leaders in Congress over the coming days about our prospects for a comprehensive agreement, as well as a path forward if we do not achieve it on July 20, including whether or not more time is needed based on the progress we've made," he said.
Observers said the statements of Zarif and Kerry, who decided to return to Washington to brief President Barack Obama and the Congress on his talks with the Iranian top diplomat, reflected a concrete progress towards addressing concerns of the western powers over the Iranian nuclear program in return of easing of sanctions on the Islamic Republic.