WASHINGTON, Aug 5 (Reuters) - The United States on Thursday urged Iran"s new President Ebrahim Raisi to return to talks on both nations resuming compliance with the 2015 Iran nuclear deal, repeating the U.S. stance that the window for diplomacy would not stay open forever. With the rise of Raisi, who took the oath of office on Thursday, all branches of power within the Islamic Republic will be controlled by anti-Western hardliners loyal to Supreme Leader Ayatollah Ali Khamenei. read more Iran has been negotiating with six major powers to revive a deal abandoned three years ago by then U.S. President Donald Trump, who said it was too soft on Tehran. The last round of talks in Vienna ended on June 20. "Our message to President Raisi is the same as our message to his predecessors .. the U.S. will defend and advance our national security interests and those of our partners. We hope that Iran seizes the opportunity now to advance diplomatic solutions," State Department spokesman Ned Price told reporters. "We urge Iran to return to the negotiations soon so that we can seek to conclude our work," Price added during a regular briefing. He said "this process cannot go on indefinitely" and at some point the benefits of reviving the 2015 agreement will have been eroded by the advancements of Iran"s nuclear program. Iran began violating the pact, which gave it sanctions relief in return for curbing its atomic program, in 2019 by conducting nuclear activities that were barred under the deal, formally called the Joint Comprehensive Plan of Action (JCPOA). Iran says its nuclear program is for peaceful purposes only.