WASHINGTON/TEHRAN, June 17 -- A proposed $300 billion private investment fund aimed at accelerating economic recovery and development in Iran has been included in the framework agreement reached between the United States and Iran, according to a source familiar with the negotiations.

The fund, known as the Reconstruction and Development Fund, is intended to encourage both sides to move toward a final agreement after reaching a preliminary framework to end months of conflict and ease tensions in the region.

According to the source, commitments exceeding $150 billion have already been secured from companies and investors across five regions, including the United States, Gulf countries, Asia, South America and Africa. The investments are e...