The White House says the July 7 deadline for nuclear talks between Iran and the global powers, including the US, could "slip”.
The two sides missed a June-end deadline pushing negotiations in Vienna into the first week of July but White House spokesman Josh Earnest said on Monday that it was “certainly possible” for the talks to be extended even further.
However, he did not “set any expectations at this point”, saying, "This (July 7) is the deadline that we continue to operate against, and that reflects the rather aggressive pace of the negotiations that are underway right now."
Last week, US Secretary of State John Kerry said the negotiators trying to reach a comprehensive agreement on Iran's nuclear energy program have their "own sense of deadline,
Iranian Foreign Minister Mohammad Javad Zarif met Kerry and his counterparts from the UK, France, Germany, Russia and Germany as well as EU foreign policy chief Federica Mogherini in Vienna earlier in the day.
The tough negotiations are aimed at clinching a high-profile political deal that will remove sanctions against Tehran in exchange for certain steps Tehran will take with regard to its nuclear program.
The Obama administration is trying to avoid giving the US Congress 60 days to review a deal therefore cannot delay its implementation later than July 9.
That way, the lawmakers will have to just approval or disapprove the deal before an August recess.