June 15 (Reuters) - Wall Street's main indexes opened higher on Monday after Washington and Tehran reached a preliminary agreement to end the Middle East conflict and reopen the Strait of Hormuz, leading to a sharp decline in crude prices.

The Dow Jones Industrial Average rose 162.3 points, or 0.32%, at the open to 51364.55. The S&P 500 rose 85.3 points, or 1.15%, at the open to 7516.75​, while the Nasdaq Composite rose 558.4 points, or 2.16%, to 26447.23 at the opening bell.