"We have made some progress, but still it is not the end of the process," Laurent Fabius told a group of reporters, stressing that all parties have adopted the principle that "nothing is agreed until the moment when everything is agreed."
Fabius said the negotiators decided yesterday that the talks will go past their June 30 target date to wait for answers to outstanding questions.
Russian Foreign Minister Sergey Lavrov will arrive in Vienna tomorrow and will meet with US Secretary of State John Kerry. Iranian Foreign Minister Mohammad Javad Zarif also is expected in Vienna tomorrow.
The United States and its Western allies believe Iran is seeking to build nuclear weapons. Iran insists its nuclear program is purely peaceful, to produce nuclear energy.
More From This Section
Fabius said that for France, which is widely viewed as taking a hardline position in the talks, there are three conditions that must be met: Limitations on Iranian nuclear research and production where "some progress has been made but it still has to be completely agreed."
Fabius said the Iranians have specific questions about how the lifting of sanctions will work "and some other elements."
He said the six major powers negotiating with Iran, the US, Russia, China, Britain, France and Germany, are also "asking some precision," but he did not elaborate.
Fabius refused to address questions about possible backtracking by Iran on previously agreed provisions. To a question on whether France is confident that Russia and China would be willing to suspend their Security Council veto power to allow sanctions to automatically be reimposed if an agreement is violated, he said, "we have very good cooperation with the Chinese and Russians."
If it isn't, Fabius warned, some countries in the region will pursue nuclear weapons. He called that "very dangerous" for the region and the world.