Iran and major powers have given themselves until Monday to reach an deal on the Iran nuclear question.
EU and US officials are extending sanctions relief for Iran to Monday.
Britain’s foreign secretary Philip Hammond said progress had been “painfully slow.”
Iran’s foreign minister Mohammad Javad Zarif has been trying to hammer out a final deal limiting his country’s nuclear programme.in return for sanctions relief.
“Some progress has been made but we are not there yet … I doubt it will happen today … it seems that were are going to spend the weekend in Vienna,” Zarif told reporters.
A senior Western diplomat reportedly said the longer the talks went on, the harder it would be to get a deal.
But a German foreign ministry spokesman said a deal is possible in the coming days, adding that, “the devil is absolutely in the detail.”