The White House on Thursday expressed confidence that the Iran nuclear agreement will take effect, despite a last-ditch effort by House Republicans to oppose it.

JOSH EARNEST, WHITE HOUSE: Well, Nancy, I believe both Majority Leader McConnell and the Senate committee chairman who wrote the legislation codifying how Congress would consider the global agreement to prevent Iran from obtaining nuclear weapons have acknowledged is that the 60 day clock for Congress’s consideration of that agreement expires on September 17th.

One reporter chose to ask the spokesman if President Obama was disappointed at not receiving Republican backing for an agreement with Iran.

As the assembled journalists burst into laughter, Mr Earnest even cracked a smile on the podium. I’m not sure what you want me to change’.

Whether or not Siri was speaking on behalf of the White House was unclear, although the answer probably reflected reasonably accurately the view of the Obama administration.

This isn’t the first time cell phones have interrupted a White House press briefing.

The Siri feature on iPhones allows users to talk into the device, allowing them to send messages, set reminders and make calls.