From Atiq Sharif

May 4 (Reuters) - Most Gulf stock markets rose slightly at the close on Monday, supported by limited signs of a possible resolution to the Middle East conflict.

US President Donald Trump said the United States would begin assisting ships stranded in the Strait of Hormuz, but he did not elaborate. The Iranian military warned US forces today against entering the waterway. Trump has made reaching a nuclear agreement with Iran a top priority, but Tehran is seeking to postpone negotiations on its nuclear program until after the war ends.

Iran's Fars news agency reported on Monday, citing local sources, that Iran had fired on a US warship attempting to cross the Strait of Hormuz, forcing it to turn back. US Central Command denied that any of its naval vessels had been attacked.

Dubai's index rose 0.2 percent, driven by a 1.7 percent increase in Emaar Properties shares.

Investors remain cautious amid ongoing geopolitical uncertainty in the region. Daniel Takieddine, co-founder and CEO of Skylinks Capital Group, said the positive momentum in regional markets linked to efforts to reopen the strait has been undermined by new developments in the waterway.

The Abu Dhabi index rose 0.3 percent, supported by gains in shares of companies linked to the major Abu Dhabi National Oil Company (ADNOC).

ADNOC Drilling shares jumped 9.2 percent, ADNOC Gas shares rose 1.2 percent, and ADNOC Logistics & Services shares also rose 1.2 percent.

The Organization of Arab Petroleum Exporting Countries (OAPEC) said on Sunday that the United Arab Emirates had withdrawn from it, after the Gulf state announced on April 28 that it had also decided to withdraw from the Organization of the Petroleum Exporting Countries (OPEC) and the OPEC+ alliance to increase production.

Leaving the oil alliances may allow the UAE to increase its production once exports resume, as it will no longer be bound by OPEC quotas.

Speculation has persisted for years that the UAE would withdraw from OPEC. Thanks to its vast reserves and some of the lowest production costs in the world, the UAE can continue to be profitable even during prolonged periods of low prices.

The Qatari index rose 0.3 percent.

The Saudi index fell 0.9 percent, affected by a 5.5 percent decline in shares of Saudi Arabian Mining Company.

But shares in Saudi oil giant Aramco rose 0.5 percent.

Brent crude futures rose $3.64, or 3.4 percent, to $111.81 a barrel by 11:24 GMT.

The Bahraini index gained 0.1 percent, the Omani index rose 0.4 percent, while the Kuwaiti index fell 0.2 percent.

Outside the Gulf region, Egypt's blue-chip index fell 0.7 percent.