LAUSANNE, Switzerland ��Iran�s chief diplomat said on Saturday that he had had productive discussions with his European counterparts and that Iranian negotiators were ready to begin drafting an initial agreement on a nuclear accord.


�I believe that France and Germany are serious about an agreement,� said Mohammad Javad Zarif, Iran�s foreign minister. �We are ready to draft.�


Western diplomats said the atmosphere in the talks was workmanlike. But they also cautioned that gaps remained and that it was still unclear if they could be bridged.


Negotiators are trying to meet a Tuesday deadline for settling on the main parameters of an accord. Once that step is taken, a comprehensive agreement with detailed technical addendums is to be finished by the end of June.


With the deadline just days away, foreign ministers from other world powers began arriving here to join Secretary of State�John Kerry�and Mr. Zarif, who have been meeting since Thursday. The arrival of the French and German foreign ministers on Saturday was generally seen as an indication that the talks were approaching a pivotal moment.


United States officials had little to say about the progress of negotiations, other than to remark that they expected the pace to intensify with the arrival of more foreign ministers. �The serious but difficult work continues,� a senior State Department official said.


Laurent Fabius, the French foreign minister, and Frank-Walter Steinmeier, the German foreign minister, met Saturday with Mr. Kerry and then separately with Mr. Zarif. Philip Hammond, the British foreign secretary, and Federica Mogherini, the European Union�s foreign policy chief, are scheduled to arrive Sunday.


French diplomats have�expressed skepticism in recent weeks�about the rush to meet the end-of-March deadline, and Mr. Fabius emphasized in his comments here that it was important that any accord be �robust.�


As a result, many observers here saw the meeting between Mr. Zarif and Mr. Fabius as particularly important.


�We�re moving forward,� Mr. Zarif said after the session.


Mr. Fabius was more circumspect, saying only that the two sides continued to work. China�s foreign minister, Wang Yi, is also heading here, a Chinese diplomat said, and Sergey V. Lavrov, the Russian foreign minister, is expected to arrive soon.


�The endgame of the long negotiations has begun,� Mr. Steinmeier said as he arrived. �The final meters are the most difficult but also the decisive ones.�


Negotiators have been at odds on a number of important issues, including what limits should be placed on the research and development of new types of centrifuges for enriching uranium, the length of an accord, and the pace at which economic sanctions on Iran should be removed.


Ali Akbar Salehi, the head of Iran�s Atomic Energy Organization, told reporters on Saturday that one or two more technical nuclear issues needed to be resolved, but he also emphasized that the questions in the talks were interrelated.


�Agreement on all issues must be reached,� Mr. Salehi said. �There are so many angles to these negotiations � political, legal and technical � and these are all connected. For example, let�s say we resolved the technical issues but not the sanctions. This would not be accepted.�


Iranian officials have�issued upbeat assessments�about the talks in recent days, perhaps calculating that doing so will build public pressure in the United States and Europe to agree to concessions on the remaining issues. Iranian diplomats have even told the Iranian news media where they hope the announcement of an accord will occur: the Palace of Nations, which houses the United Nations headquarters in Geneva.


Everybody, it seemed, anticipated more intensive late-night negotiating sessions. Asked at the start of his meeting with Mr. Zarif on Saturday if he expected a good day, Mr. Kerry said dryly, �We�re expecting an evening today.�


�Evening, night, midnight, morning,� Mr. Zarif added.


By The New York Times