An escalation of fighting in Lebanon and the ongoing one-year-old war between Israel and Hamas in Gaza has raised fears of a wider Middle East conflict.
Rocket sirens sounded constantly across northern Israel on Wednesday, including in the major port city of Haifa, following heavy fire from Lebanon. Israel's military said about 40 projectiles were launched in one barrage at Haifa, some of which were intercepted while others fell in the area.
The downturn in Gulf markets began after Iran launched a missile barrage on Israel on Oct. 1. Israel has sworn to retaliate and is weighing its options, with Iran's oil facilities considered a possible target.
Saudi Arabia's benchmark index (.TASI), opens new tab dropped 0.8%, weighed down by a 1.1% fall in aluminium products manufacturer Al Taiseer Group (4143.SE), opens new tab and a 2% decline in Al Rajhi Bank (1120.SE), opens new tab.
Elsewhere, oil giant Saudi Aramco (2222.SE), opens new tab was down 0.4%.
Oil prices - a catalyst for the Gulf's financial markets - erased early gains as weak demand fundamentals and rising supply countered the elevated risk of supply disruption from conflict in the Middle East and Hurricane Milton in the United States.
Dubai's main share index (.DFMGI), opens new tab eased 0.2%, with top lender Emirates NBD (ENBD.DU), opens new tab losing 1%.
In Abu Dhabi, the index (.FTFADGI), opens new tab edged 0.3% higher.
Outside the Gulf, Egypt's blue-chip index (.EGX30), opens new tab advanced 1.1%, as most of its constituents were in positive territory, including Talaat Mostafa Holding (TMGH.CA), opens new tab, which was up 2.9%.