Iran's government is downplaying the possibility of reaching a nuclear agreement by the end of March.
Iranian Foreign Minister Mohammad Javad Zarif says Iran's position remains unchanged, saying no agreement will be reached unless all issues are agreed upon.
"Political will must be seen in action. Everyone claims that the political will is there. In fact, we must see whether the political will for reaching a solution exists or not," said Zarif.
The suggestion comes on the heels of comments by the White House, which has suggested the US side is less than 50-50 about reaching a deal before the end of this month.
Kelsey Davenport with the U.S.-based Arms Control Association suggests the comments may be mostly bluster. "Well, I think that that's possible but the negotiators have given themselves until June to complete the entirety of the deal. However both sides are facing domestic political pressure, particularly within the United States. The Obama administration faces a Congress that has taken some actions recently to derail the talks, so they know the time to complete this is now and I think they can do it before the end of March."
Senior officials from the 5 permanent members of the UN Security Council, plus Germany, are expected to join the talks in Switzerland later on today following the conclusion of the bilateral talks between the US and Iran.
Iran and six world powers have been working on an agreement to limit Iran's nuclear programme in exchange for a gradual lifting of sanctions on Tehran.
A framework agreement is supposed to be finished by the end of this month.
A final deal is to be concluded by the end of June.
