Iran requested “some adjustments” to a draft agreement on reviving a 2015 nuclear accord with major powers proposed by the European Union, the bloc’s foreign policy chief Josep Borrell said Tuesday.

During an interview with Spanish public television TVE, Borrell said “most” countries involved in nuclear talks with Iran agreed with the proposal, but that the United States had not yet responded.

The 2015 agreement between Iran and six world powers — Britain, China, France, Germany, Russia and the United States — gave the Islamic republic sanctions relief in exchange for curbs on its nuclear program.

“Iran responded by saying ‘yes but’, that is to say they want some adjustments,” Borrell told TVE, without providing further details.

During a press conference Monday in Santander in northern Spain, he said Iran’s response had seemed “reasonable” to him and it was therefore submitted to the six world powers involved in the nuclear talks.

“We are waiting for their response, most of them agree, but there is still no answer from the United States… we expect to receive a reply during this week,” he added.