Most stock markets in the Gulf ended lower on Wednesday over Omicron worries and as investors worldwide await the U.S. Federal Reserve's plan to wind down asset purchases and start raising interest rates.

The Fed's decision will set the tone for the central banks of the European Union, the UK and Japan when they meet this week, and add to pressure for policy tightening in emerging markets. 

Omicron coronavirus variant fears impacted risk appetite as current vaccines are deemed less effective, said Farah Mourad, senior market analyst of XTB MENA.

In Abu Dhabi, the index dropped 0.3%, pressured by a 0.3% fall in the country's largest lender First Abu Dhabi Bank.

Dubai's main share index dropped 0.7%, snapping a 10-session winning run triggered after announcements of upcoming initial public offerings.

Last month, the government announced plans for 10 state-backed companies to be listed as part of efforts to boost activity on the local bourse.

The listings are aimed at making Dubai a more competitive market in the region, as bourses in Saudi Arabia and Abu Dhabi see larger listings and strong liquidity.

Sharia-compliant lender Dubai Islamic Bank and Emirates NBD Bank dropped 1.1% each.

On the other hand, National General Insurance Co added 0.6%, after it received an offer from Dubai Investments to gain full ownership of the company, in a deal that values the insurer at nearly 468 million dirhams ($127.43 million).

The Qatari benchmark declined 0.7%, dragged down by a 2.3% slide in petrochemical maker Industries Qatar.

Saudi Arabia's benchmark index advanced 1.1%, buoyed by a 1.6% rise in Al Rajhi Bank and a 2% jump in the kingdom's biggest lender Saudi National Bank.

The Saudi market, which advanced after declining for two consecutive sessions ahead of the Federal Reserve meet, continues to be supported by local economic fundamentals, said Mourad.

($1 = 3.6726 UAE dirham)

(Reporting by Ateeq Shariff in Bengaluru; Editing by Vinay Dwivedi) ((AteeqUr.Shariff@thomsonreuters.com; +918061822788;))