U.S. President Barack Obama says it has not yet been determined if nuclear talks with Iran will be extended beyond Sunday's deadline for a deal.
Obama said Wednesday that real progress has been made, but there are still significant gaps as the deadline approaches.
He said discussions with Iran and consultations with Congress will continue as the United States and its partners determine if more time is needed.
Iranian Foreign Minister Mohammad Javad Zarif said this week that the process is worth continuing. The foreign minister said he is sure U.S. Secretary of State John Kerry will make the same recommendation.
An interim deal for Iran to curb its uranium enrichment in exchange for an easing of sanctions expires July 20. Diplomats from Britain, China, France, Germany, Russia, and the U.S. have been working with Iran on a longer term deal.
White House Secretary Josh Earnest said "Iran's track record over the last six months has been surprisingly favorable." But he echoed Secretary of State John Kerry's sentiment that a number of gaps remain before diplomats from Tehran and world powers can reach a deal.
A Western diplomat says it is highly improbable a deal can be reached by Sunday and that the talks would continue over the coming months.
The U.S. suspects Iran of trying to build a nuclear weapon. Iran insists its nuclear program is strictly for peaceful purposes.