US Secretary of State John Kerry says progress has been made in intense negotiations between Iran and the P5+1 group of countries on Tehran’s nuclear energy program.
"I think we have resolved some of the things that were outstanding and we've made some progress," Kerry told a group of reporters in Vienna on Friday.
The top US diplomat praised the "constructive" atmosphere.
Iran and the P5+1 countries - the United States, Britain, France, Russia, China and Germany - have been engaged in crucial talks in the Austrian capital, Vienna, towards reaching a landmark agreement over Tehran’s nuclear energy program.
The negotiating sides missed an initial deadline of June 30 and all parties agreed on a new July 7 deadline. Now it seems that negotiations will continue at least until Monday.
On April 2, Iran and the P5+1 group reached a mutual understanding on Tehran’s nuclear program after eight days of marathon talks in the Swiss city of Lausanne.
The US and its allies allege that Iran is pursing nuclear weapons, Tehran, however, denies the allegation, saying that it needs nuclear power for peaceful purposes.