The United States, encouraged by the signals sent by Iran’s election of Hassan Rouhani, hopes Iran engages seriously and gives a substantive response when nuclear talks resume in the fall, a senior US administration official said Friday.

“We have all noted Rouhani’s positive tone and remarks post-election,” the senior US administration official said in a small background conference call briefing Friday.

“We are glad for the positive words," the official continued. "But what we are looking for are actions that indicate a desire to deal seriously with the P5+1. Words are not enough. We need a concrete response.”

The American official spoke ahead of a meeting of political directors from the P5+1--the United States, United Kingdom, France, Germany, Russia and China--in Brussels next week (July 16 ) to discuss preparations for a new meeting with Iran in the fall. Talks between the P5+1 and Iran are likely to resume at the earliest in September, following the inauguration next month of Rouhani, and depending on the logistics of arranging a meeting around the opening of the United Nations General Assembly in September.