As what was supposed to be the final round of talks between the P5+1 group of world powers and Iran over a comprehensive agreement on the Iranian nuclear programme was heading to the end of its second, unscheduled week, it was unclear whether a deal could be reached, or whether a deadline to achieve one still existed.
The talks, in Vienna, had been extended until this Tuesday as negotiators continued to grapple with key issues.
As the deadline loomed, European Union foreign policy chief Federica Mogherini told the press that it would take "a few more hours or a couple of days".
On Tuesday afternoon, a United States State Department spokeswoman said the interim agreement, signed in November 2013, and intended originally to last for six months, was once again being extended - this time by three days until Friday night.
