WASHINGTON, June 17 (Reuters) - The United States has so far not released the full text of the interim U.S.-Iran agreement to halt the war in Iran and open the Strait of Hormuz. But a draft copy reviewed by Reuters lays out in 14 points a high-level understanding that defers until a final agreement is signed many of the most difficult issues, such as how to wind down Iran's nuclear program. It paves the way for a broader 60-day negotiation period due to begin in Switzerland on Friday.