The Washington Post reports that U.S. Congress has not submitted a bill to the White House this summer to strengthen sanctions against Iran as it has customarily done, and instead delayed such a bill until at least October, opening a window of opportunity for diplomatic engagement with Iran.

In another move toward diplomacy, earlier this week 130 members of Congress signed a letter addressed to the U.S. president, urging that he take a more diplomatic approach in dealing with Iran. The signatories write: “We believe it would be a mistake not to test whether Dr. Rouhani’s election represents a real opportunity for progress toward a verifiable, enforceable agreement. … In order to test this proposition, it will be prudent for the United States to utilize all diplomatic tools to reinvigorate ongoing nuclear talks.”

Iranian Parliament’s head of National Security and Foreign Policy acknowledged the change in the U.S. approach, adding that it is not yet clear whether “this will be a transient development or if it could have a meaningful outcome.”

Unilateral U.S. sanctions on Iran’s oil and financial sectors have further strained Iran-U.S. relations, which have been fraught with animosity since the 1979 Iranian Revolution and the establishment of the Islamic Republic.

Iranian president-elect Hassan Rohani has promised to take a more conciliatory approach to international relations.