German Foreign Minister Guido Westerwelle says talks on Iran's nuclear program are "not a done deal."
Westerwelle told reporters on November 23 that six major world powers and Iran have yet to work on their disagreements to conclude an agreement.
"There are still differences we have to bridge," he said. "It is not a done deal. We have come to Geneva to support and to do our utmost that we reach an agreement. We think there is a realistic chance but there is still a lot of work to do."
On the same day, British Foreign Secretary William Hague also indicated that remaining gaps between Iran and the six powers were significant.
"They remain very difficult negotiations, I think it's important to stress that," he said. "We are not here because things are necessarily finished. We are here because they are difficult and they remain difficult. There are narrow gaps, but they are important gaps."
Russian Deputy Foreign Minister Sergei Ryabkov told the RIA-Novosti news agency that the talks were very close to a breakthrough but there was no assurance of achieving an agreement.
Foreign ministers of the 5+1 group -- comprising the United States, Russia, China, United Kingdom, and France, plus Germany -- are convening in Geneva on November 23 amid hopes of a breakthrough in talks with Iran over that country's controversial nuclear actitivities.
Westerwelle and U.S. Secretary of State John Kerry and the foreign ministers of Britain, France, China, and Russia are throwing their weight behind a diplomatic push to complete a deal after envoys reported progress on key issues blocking an interim agreement to curb the Iranian program in return for limited sanctions relief.
Speaking before leaving Washington for Geneva, Kerry said he had no particular expectation that an agreement could be reached this week but decided to come after talking with top European Union diplomat Catherine Ashton on November 22.
A State Department spokeswoman later said Kerry would leave Geneva for London on November 24 for talks with British Foreign Secretary William Hague.
EU foreign policy chief Catherine Ashton and Iranian Foreign Minister Mohammad Javad Zarif reportedly made "progress" on "core issues" during talks earlier on November 22.
Chinese media quoted a Foreign Ministry source as saying the talks "have reached the final moment."
The P5+1 group of world powers are offering Iran limited relief from sanctions in exchange for a suspension of some aspects of its nuclear program.
Zarif told journalists on November 23 that some three or four other differences remain, including Iran's Arak heavy-water reactor and the extent of the sanctions relief being offered.
Some proposals include releasing Iran's funds frozen in foreign bank accounts and allowing trade in metals, petrochemicals, and aircraft parts.
Tehran is seeking a more sweeping easing of sanctions against its oil industry and a lifting of restrictions on its use of international banking.
It is the second time in two weeks that the foreign ministers of the P5+1 countries have converged on Geneva amid hopes of an agreement in the long-stalled talks
With reporting by Reuters, AP, and AFP