The State Department has announced that US Secretary of State John Kerry is to travel to Vienna to join talks over Iran's nuclear program as the deadline for an agreement nears.
State Department spokeswoman Jen Psaki said Kerry would meet with the US negotiating team in Austria before holding talks with other parties.
Kerry was holding discussions in Paris with the Saudi foreign minister, Saud Al Faisal, before meeting French foreign minister Laurent Fabius.
Negotiators are rushing to complete a deal in the next five days to stop Iran having the capability to produce nuclear weapons.
The head of the International Atomic Energy Agency (IAEA) released a statement, saying that Iran had not "provided any explanations that enable the agency to clarify the outstanding practical measures".
He called on Iran to "increase its cooperation with the agency and to provide timely access to all relevant information, documentation, sites, material and personnel".