Nuclear talks pause after limited progress

VIENNA — A crucial round of negotiations over Iran’s nuclear program ended abruptly yesterday with Western diplomats acknowledging that they had made less headway than they had hoped and complaining that Iran is holding up their effort to seal a historic deal in the next nine weeks.

After three days of negotiations, diplomats for Iran and six world powers found themselves “at a moment of great difficulty,” a senior U.S. official said.

“Significant gaps remain,” the official added. “There needs to be more progress, and it needs to come more quickly.”

The European Union’s foreign policy chief, Catherine Ashton, and Iranian Foreign Minister Mohammad Javad Zarif left Vienna without making closing public statements. The chief U.S. negotiator, Undersecretary of State Wendy Sherman, also left as soon as the meetings ended yesterday.

Iran and six world powers are trying to reach a deal under which Iran would accept limits on its nuclear program in exchange for an easing of international sanctions on its economy. The six governments want to prevent Iran from attaining nuclear-weapons capability.

This week’s sessions were key because the negotiators were beginning to draft the text of a deal.

Western officials said the slowdown was expected. The U.S. official insisted that the diplomats still hope to reach a deal by July 20.