"We have never been so close to a deal as now. But the truth is that the final phase of the talks that lie before us is probably the most difficult," Frank-Walter Steinmeier told reporters on Thursday after sitting down with Rouhani at the Iranian delegation's hotel in New York, on the sidelines of the UN General Assembly meeting.

Progress has been made in recent months towards a deal between Iran and negotiators from the five permanent members of the UN Security Council - China, Britain, France, Russia and the United States - plus Germany.

Western countries accuse Iran of using its nuclear energy program to develop a weapon. Tehran denies those accusations, saying its efforts are for peaceful, scientific purposes.

Nuclear negotiators have been meeting during the UN General Assembly meeting this week. A November 24 deadline to reach a deal looms, but an extension has been granted in the past.

Steinmeier acknowledged "there are still hurdles to get over." But he stressed that there was no time to lose when it came to resolving the dispute.

"Now is the time to end this conflict," he said. "I hope that Iran … in view of the situation in the world and the situation in the Middle East, knows and senses that a collapse of the talks now is not permissible."

dr/jm (dpa, Reuters)