UAE's stock markets ended lower on Wednesday after the country said it detected two ballistic missiles launched from Iran, while other Gulf bourses were subdued after Washington said there were no talks with Tehran to end hostilities.
The United Arab Emirates said the missiles, the first such since a May 4 strike on Fujairah port, appeared to target maritime traffic and fell into the sea.
Iran's foreign ministry dismissed the allegation as "baseless."
UAE later said it was suspending all trade activities, commercial exchanges and financial transactions with Iran until further notice.
Abu Dhabi's benchmark index fell 0.9%, weighed down by financial, telecom, consumer discretionary and utility stocks.
First Abu Dhabi Bank, the country's largest lender, lost 2.8% while ADNOC Gas declined 0.9%.
Dubai's benchmark index slipped 0.3%, with most sectors in negative territory. Emirates NBD dropped 3% while Spinneys 1961 Holding fell 1.6%. Parking operator Parkin Company, however, rose 2.1% after saying it had signed memorandums of understanding with three Egyptian companies to explore smart-parking projects in Egypt.
Qatar's benchmark index extended losses for a third consecutive session, and fell 0.8% to 9,773 points — its lowest in more than a year.
Qatar National Bank, the region's largest lender, fell 1.8%, while Qatar Fuel Company dropped 3.9%.
Saudi Arabia's benchmark index edged up 0.2%, supported by a 2.4% rise in National Shipping Company of Saudi Arabia and a 4.2% gain in Seera Holding.
"GCC stock markets will likely remain affected by the current regional situation, with investors continuing to monitor material developments and the potential for a return to U.S.-Iran talks," said Daniel Takieddine, co-founder and CEO of Sky Links Capital Group.
"However, downside risks remain limited as markets continue to benefit from strong local fundamentals."
Outside the Gulf, Egypt's blue-chip index fell for a third straight session, closing 1.4% lower as most shares ended in negative territory. Commercial International Bank lost 1.8%, while Telecom Egypt declined 2.9%.
SAUDI ARABIA up 0.1% to 10,926
DUBAI down 0.3% to 5,842
ABU DHABI fell 0.9% to 10,006
QATAR down 0.8% to 9,773
KUWAIT up 0.4% to 9,248
BAHRAIN down 0.1% to 1,945
OMAN ended flat at 7,547
EGYPT fell 1.4% to 54,513