The US said on Monday it expected indirect talks with Iran about both sides.
Iran and the US had said on Friday they would hold indirect talks in Vienna as part of a wider effort to revive the nuclear deal between Tehran and global powers.
Tehran has ruled out face-to-face bilateral discussions and state department spokesman Ned Price told reporters at his daily briefing on Monday that the US did not expect any “at present”. The talks begin on Tuesday.
US special envoy for Iran Rob Malley, a veteran of the Clinton and Obama administrations, will lead the US delegation to the talks.
“We don’t underestimate the scale of the challenges ahead,” US State State Department Spokesperson Ned Price said on Monday.
“These are early days. We don’t anticipate an early or immediate breakthrough as these discussions, we fully expect, will be difficult.”