Lately the markets have been under pressure on worries that Israel would attack Iran in retaliation for the latter's Oct. 1 missile strike.
Russia is warning Israel to not even consider striking Iranian nuclear facilities, state news agency TASS quoted Deputy Foreign Minister Sergei Ryabkov as saying on Thursday.
The statement was attached to a Washington Post article which said Netanyahu had told President Joe Biden's administration that Israel would strike Iranian military targets, not nuclear or oil targets.
Saudi Arabia's benchmark index (.TASI), opens new tab dropped 1.1%, with aluminium products manufacturer Al Taiseer Group (4143.SE), opens new tab losing 1.8% and Al Rajhi Bank (1120.SE), opens new tab sliding 2.9%.
The kingdom's crude oil exports in August fell to their lowest level in a year, data from the Joint Organizations Data Initiative (JODI) showed on Thursday.
Among other fallers, oil giant Saudi Aramco (2222.SE), opens new tab eased 0.4%.
Oil prices - a catalyst for the Gulf's financial markets - were broadly flat as investors waited on developments in the Middle East, the release of official U.S. oil inventory data and details on China's stimulus plans.
Dubai's main share index (.DFMGI), opens new tab dropped 0.6%, with top lender Emirates NBD (ENBD.DU), opens new tab declining 2.7% after reporting a flat third-quarter net profit, as an increase in net interest income was offset by higher impairment charges and investments to drive future growth.
In Abu Dhabi, the index (.FTFADGI), opens new tab lost 0.3%, weighed down by a 1.8% drop in the United Arab Emirates' biggest lender First Abu Dhabi Bank (FAB.AD), opens new tab ahead of its earnings announcement.
The Qatari index (.QSI), opens new tab finished flat, with Commercial Bank (COMB.QA), opens new tab retreating 2.2% after the lender posted a mere 2.6% increase in nine-month net profit.
Outside the Gulf, Egypt's blue-chip index (.EGX30), opens new tab concluded 1.3% lower, with tobacco monopoly Eastern Company (EAST.CA), opens new tab tumbling 6.3%.