US Secretary of State Antony Blinken said a potential nuclear deal with Iran was still close, but cautioned that "a couple of very challenging remaining issues" were still unresolved.
The move is not a signal that Washington was about to reach an understanding to return to the nuclear deal.
European officials have balked at the proposed changes to a painstakingly drafted text that they say is 70-80% finished.
There have been four wild developments on Wednesday and in recent days which will have major impacts on the future of the Iranian nuclear standoff.
PM hopes to cooperate with Biden administration, thankful to US president for supporting Israel in last Gaza war
"We will have to see how in the coming days we address these violations with the will to press ahead in the talks."
"The Zionists want to take revenge because of our progress in the way to lift sanctions... We will not fall into their trap...We will not allow this act of sabotage to affect the nuclear talks."
"Things are moving in the right direction, and we have had positive signals this week and especially in the last few days," a French diplomatic source said.
The US was "disappointed" with the Iranian response, a White House official reportedly to Walla News.
"The president's been very clear publicly, repeatedly, about where we stand. And we'll see what, if any, reaction Iran has to that," he said.