Germany's foreign minister said Thursday no more deadlines must be missed in the Iran nuclear negotiations which had entered "a decisive phase", speaking at a meeting with his Iranian counterpart.
"We must now use the newly opened time window, we must leave nothing undone to reach the solution that has eluded us in recent years," Frank-Walter Steinmeier said before the talks with Iranian Foreign Minister Mohammad Javad Zarif.
In a brief joint press appearance with Zarif, Steinmeier said "we probably share the understanding that this is now the decisive phase of the negotiations".
Iran and major world powers have given themselves until late June to reach a comprehensive agreement that would prevent Tehran from developing a nuclear bomb, a goal it denies, in return for an easing of global sanctions.
Sunday will see talks in Geneva between Iran and the so-called P5+1 group -- the United States, Britain, China, France, Germany and Russia -- seeking to break a stalemate that has seen two earlier deadlines pass without an accord.
Steinmeier said that "we have extended this transition agreement twice, but we also agreed at the last meeting that we share the common understanding that one cannot indefinitely continue the extensions".
"Iran's path to nuclear weapons must end unambiguously, verifiably and permanently, and in return sanctions must be lifted credibly and step-by-step," Steinmeier said.
He added that this would restore trust between all sides as they faced a host of crises and conflicts such as the threat posed by the Islamic State jihadist group in Iraq and Syria
Zarif was visiting Steinmeier in Berlin, a day after holding talks with US Secretary of State John Kerry in Geneva and a day before he was set to meet French Foreign Minister Laurent Fabius in Paris
The Iranian minister said through a translator that "we have lost 11 years, and the conditions have not become better. And that's why we need to seize the opportunity to achieve justice, peace and security, and I'm certain that with the participation of Germany ... we can reach this goal."