June 17 (Reuters) - Major Gulf stock markets traded mixed on Wednesday as investors assessed the implications of an interim peace agreement between the United States and Iran.

Some details of the accord emerged on Tuesday, with President Donald Trump saying the arrangement would prevent Tehran from acquiring a nuclear weapon. A U.S. official indicated that Iran would be permitted to resume oil sales once the deal is signed on Friday.

The memorandum of understanding extends a fragile ceasefire reached in April by 60 days, allowing more time for negotiations toward a lasting settlement.

Under the proposed terms, the United States would lift its blockade of Iranian ports, while Tehran would restore oil tanker passage through the Strait of Hormuz, which has been effectively shut since the war started in late February.

Saudi Arabia's benchmark index .TASI edged 0.1% lower, weighed down by a 0.9% fall in oil major Saudi Aramco 2222.SE.

Brent crude futures LCOc1 were down 0.2%, or 15 cents, at $78.81 a barrel by 0630 GMT.

Separately, the kingdom's new airline, Riyadh Air, won the right to operate flights to and from the United States, the U.S. Transportation Department said in an order Tuesday.

Dubai's main share index .DFMGI gained 0.3%, helped by a 0.8% rise in blue-chip developer Emaar Properties EMAR.DU.

In Abu Dhabi, the index .FTFADGI was down 0.1%.

The Qatari benchmark .QSI added 0.3%, with Qatar National Bank QNBK.QA, the Gulf's biggest lender, rising 0.3%.