Germany's Foreign Minister Annalena Baerbock said that time was running out to find a way to revive a 2015 nuclear deal between world powers and Iran.
She was speaking after meetings with her counterparts from the G7 countries in Liverpool, England.
Talks have resumed in Vienna to try to revive the nuclear pact, with both sides trying to gauge the prospects of success after the latest exchanges in the stop-start negotiations.
“Time is running out,” Ms Baerbock told reporters. “It has shown in the last days that we do not have any progress.”
She said Iran had resumed the talks with a position that set the negotiations back by six months. The current round of talks in Vienna comes after a pause of five months after the election of Ebrahim Raisi, a hardline anti-westerner, as Iran's president.
Earlier, US officials said Secretary of State Antony Blinken had held a “productive” meeting with counterparts from Britain, Germany and France on Friday to discuss the way forward for the Iran talks.
A senior State Department official said there was an “intense” conversation among the G7 countries, which were united in their position on the nuclear talks.
“The statement will also be strong on the importance of getting Iran back to the table and that it is possible to conclude a deal but that the time is shrinking, so we are united in that,” the official said.
The official said US Special Envoy for Iran Robert Malley was heading back to Vienna for talks.
Iranian officials have previously said they were sticking to their tough stance.
Under the original nuclear deal, abandoned in 2018 by former US president Donald Trump, Iran limited its nuclear programme in return for relief from US, EU and UN sanctions.
The West fears the programme would be used to develop weapons, something Tehran denies.
Mr Raisi said on Saturday that Tehran was serious in its nuclear talks in Vienna, the official IRNA news agency reported.
The indirect US-Iranian talks, in which diplomats from France, Britain, Germany, Russia and China shuttle between them because Tehran refuses to have direct contact with Washington, aim to ensure both sides resume full compliance with the accord.
The G7 meeting is expected to result in a joint call for Iran to moderate its nuclear programme and grasp the opportunity of the Vienna talks.