Iran has rejected a statement by France, Britain and Germany who said on Saturday they had "serious doubts" about Tehran's intentions to reach a nuclear deal.
Iran earlier this month sent its latest response to the European Union's proposed text to restore the 2015 agreement, or the JCPOA.
Iran insists on the closure of investigations by the International Atomic Energy Agency (IAEA) into uranium traces at three sites.
The IAEA's Board of Governors meet on Monday, three months after adopting a resolution urging Iran to give credible answers to the watchdog on the issue. Ahead of that meeting the European parties to the deal vented their frustration.
"This latest demand raises serious doubts as to Iran's intentions and commitment to a successful outcome on the JCPoA," the three countries, known as the E3, said in a statement.
"Iran's position contradicts its legally binding obligations and jeopardizes prospects of restoring the JCPoA."
Iran's Foreign Ministry spokesperson Nasser Kanaani said the statement was "unconstructive.”
"If such an approach persists, they (E3) should also take responsibility for its consequences," Kanaani said without elaborating.
The European statement also prompted Russia's envoy to the talks to respond on Twitter calling it "very untimely indeed". He dismissed the blockage as something that "was not a serious obstacle".
Highlighting how entrenched positions are before next week, France's negotiator, Philippe Errera, called out his Russian counterpart.
"There is no longer an active negotiation, since Iran's last response - which you, unlike almost all your followers, have had access to," he said on Twitter.
Ulyanov responded that at least they agreed that there was no active negotiation.
Reporting by Reuters