By Ateeq Shariff

May 24 (Reuters) - Most Gulf stock markets closed sharply higher on Sunday as geopolitical risk premiums eased on news that Washington and Iran were nearing a peace deal that would also reopen the strategic Strait of Hormuz.

U.S. President Donald Trump announced that Washington and Iran have "largely negotiated" a memorandum of understanding to end their three-month-old war and reopen the strait, the vital shipping passage whose closure has sparked a global energy crisis.

Trump said on his Truth Social platform that the final details of the agreement were currently being discussed and would be announced shortly.

In Qatar, the main share index .QSI jumped 3.2% - its biggest intraday gain since April 8 - as all its constituents were in positive territory including Qatar National Bank QNBK.QA, which gained 4.7%.

Although a deal securing the fragile ceasefire would offer market relief, the global energy crisis — and the resulting high costs of fuel, fertilizer, and food — is expected to persist in the near term.

Bahrain's main index .BAX advanced 1.7%, while Kuwait's .BKP was up 2%.

Outside the Gulf, Egypt's blue-chip index .EGX30 ended 1.5% higher, with Commercial International Bank COMI.CA rising 3.4%.

The Saudi market remained closed ahead of the upcoming Eid break.