DUBAI  - Gulf stocks were trading in a narrow range early on Tuesday as investors paused ahead of a U.S. Federal Reserve policy meeting and amid concerns that U.S. President Donald Trump could impose additional protectionist trade measures.

Oil prices edged up slightly, with Brent crude futures up 21 cents at $66.26 per barrel. The Fed's first policy meeting under new chairman Jerome Powell begins later in the day.

The region's biggest market, Saudi Arabia, was 0.1 percent lower, weighed down by banks. National Commercial Bank was down 0.4 percent and Samba Financial Group dropped 0.5 percent.

The Abu Dhabi index slipped 0.3 percent with Aldar Properties down 0.9 percent, and First Abu Dhabi Bank (FAB)  down 0.4 percent.

On Monday FAB, the United Arab Emirates' biggest lender, denied that it had tried to manipulate the Qatari riyal.

The denial came after Reuters reported that a law firm working for the central bank of Qatar asked U.S. regulators to investigate FAB's U.S. subsidiary, accusing it of "bogus" foreign exchange deals designed to harm Qatar's economy.

The Dubai index was flat, as banks edged higher, but construction stocks and smaller property firms weighed.

Emaar Properties was up 0.3 percent, and Dubai Islamic Bank was up 0.2 percent. Union Properties was down 0.6 percent and Drake & Scull International was down 0.6 percent.

In Qatar, the index was down 0.3 percent. Industries Qatar lost 1.8 percent and United Development Company lost 1.2 percent.

Qatar National Bank, which had attracted buying interest due to its move to boost foreign ownership limit, came in for selling on Tuesday. It was down 1.5 percent in early trade.

(Reporting by Hadeel Al Sayegh Editing by Catherine Evans) ((Hadeel.AlSayegh@thomsonreuters.com; +971566883310;))