DUBAI, Feb 28 (Reuters) - Dubai's stock index outperformed in an otherwise weak Gulf region in early trade on Tuesday as investors bought shares that had recently fallen.

The Dubai index added 0.5 percent, with advancing shares outpacing declining ones by 17 to three. Small-to-mid sized stocks were the top gainers, with Union Properties climbing 4.0 percent. Shares of telecommunications operator Etisalat, the largest stock on Abu Dhabi's exchange, fell 1.1 percent to be the main drag on the index, which was down 0.2 percent.

Qatar's index slipped 0.5 percent, weighed down by banking shares; Qatar National Bank fell 1.6 percent.

Saudi Arabia's index extended the previous session's 1.1 percent decline, dropping 0.3 percent as all but two of the 12 listed banks fell. Saudi British Bank lost 1.2 percent.

Real estate investment trust Riyad REIT was the most heavily traded stock, falling 3.3 percent. On Monday it slumped its 10 percent daily limit.

(Reporting by Celine Aswad; Editing by Andrew Torchia) ((celine.aswad@thomsonreuters.com)(+9715 62247653)(Reuters Messaging: celine.aswad.thomsonreuters.com@reuters.net))