* Banks generally weak in Saudi, most REITs down
* DP World falls on uninspiring first-half results
* Dana Gas supports Abu Dhabi
* Qatar worst performer in the region
* Egypt's Orascom Construction drops on net profit decline
DUBAI, Aug 24 (Reuters) - Most stock markets in the Middle East declined on Thursday as local retail investors booked profits and institutional investors stayed on the sidelines, while Dubai port operator DP World underperformed because of uninspiring interim earnings.
"The region has been a retail-, momentum-driven market and I expect next week that trend will spill over," said a Dubai-based portfolio manager. With Eid al-Adha holidays due to start in the region from the middle of next week, many retail investors are starting to book profits.
The Riyadh index fell 0.3 percent, snapping six straight sessions of gains, as a little over half of banks fell including one of this week's top-performing stocks, Al Rajhi Bank, which retreated 0.9 percent.
Most real estate investment trusts, which have been very active over the last several sessions, fell with Taleem REIT dropping 2.4 percent.
The Dubai index closed flat after trading higher for most the day. Emaar Properties rose 1.3 percent but theme park operator DXBE Entertainments fell 0.8 percent.
The Dubai-listed shares of Bahrain's GFH Financial Group rose 1.1 percent after the company said its board had discussed distributing dividends "given the group's recent good performance". It said it was consulting Bahrain's central bank on what level of dividend would be appropriate.
The Middle East's largest listed port operator, DP World , fell 1.6 percent after the company reported a first-half net profit of $606 million, in line with analysts' expectations.
Profit was flat compared to the year-ago period but revenue was up almost 10 percent. The company said its like-for-like revenue rose 3 percent, driven mainly by an increase in containerised revenue.
The Abu Dhabi index added 0.1 percent, gaining strength in the final hour of trade on the back of a 3.2 percent rise in Dana Gas.
In Doha, the index fell 1.1 percent in very thin trade as four-fifths of the 20 most valuable shares declined including Qatar National Bank, which lost 2.2 percent.
The index has been in a downtrend since late July, reversing some of the gains it made that month after a June sell-off that was triggered by the severing of diplomatic and trade links between Qatar and four other Arab states on June 5.
"Qatar has been underperforming its emerging market peers because of the political deadlock - money likes visibility and clarity," said a regional portfolio manager in Beirut.
Kuwaiti telecommunications company Zain rose 1.0 percent. After the market closed, Zain said Oman Telecommunications had completed the purchase of a 9.84 percent stake in the company through a public auction of treasury shares in a deal which was previously announced.
Zain group chief executive Bader Nasser al-Kharafi told reporters that proceeds from the transaction would be used to reduce debt and improve its operations. Omantel fell 0.4 percent on Thursday and the Kuwait index fell 0.5 percent.
In Egypt, Orascom Construction sank 5.7 percent after it reported a 10.2 percent drop in second-quarter net profit attributable to shareholders. Revenue for the period also fell. The Cairo index slipped 0.5 percent.
* The index fell 0.3 percent to 7,246 points.
* The index edged down 0.01 percent to 3,624 points.
* The index rose 0.1 percent to 4,494 points.
* The index lost 1.1 percent to 8,952 points.
* The index fell 0.5 percent to 12,926 points.
* The index declined 0.5 percent at 6,885 points.
* The index fell 0.2 percent to 1,302 points.
* The index lost 0.2 percent to 4,947 points. (Editing by Andrew Torchia/Mark Heinrich)