Abu Dhabi's two main property stocks dropped, pushing the index to a new 21-month closing low.
Aldar Properties fell 5.4 percent and Sorouh Real Estate ended 4.7 percent lower. Both had dropped more than 7 percent intraday.
"Investor focus is shifting back to fundamentals and with the recent delays and cancellations in Abu Dhabi real estate projects, it would be hard to imagine from where these developers will continue to generate cash going forward," said Amer Khan, fund manager at Shuaa Asset Management.
Abu Dhabi government-owned Tourism Development and Investment Co (TDIC) said in October it was postponing the opening of three museums, in a fresh delay for one of the largest cultural projects in the Middle East.
Abu Dhabi's index fell 0.8 percent to 2,393 points, its lowest close since March 2009.
Pressure from a weak global backdrop outweighed selective stock buys and strong local fundamentals in Saudi Arabia, with the index halting three sessions of gains.
The benchmark slipped 0.1 percent to 6,258 points, extending year-to-date losses to 5.5 percent.
"It's global factors... the eurozone deal unravelling and North Korea," said Paul Gamble, head of research at Jadwa Investment. "We've had a reasonable run recently, so there may be an element of natural profit-taking."
Petrochemical stocks led the decline with Saudi Basic Industries Corp (SABIC) falling 1.1 percent and National Industrialisation slipping 0.8 percent.
Advanced Petrochemical was the largest support to the index, rising 2.4 percent after saying it will pay a SAR1-per-share ($0.27) cash dividend for the second half of 2011.
It will also raise its capital by issuing one bonus share for every 6.25 held and raise its total paid-up capital from SAR1.41bn to SAR1.64bn, it said in a bourse statement on Monday.
Saudi Chemical Company climbed 3 percent. It said on Sunday it will distribute a SAR2-per-share cash dividend for the third-quarter. Dec 28 is the ex-dividend date.
Saudi billionaire Prince Alwaleed bin Talal's investment firm Kingdom Holding gains 3.8 percent after it and the prince bought a $300m stake in microblogging site Twitter. The stock rose over 8 percent at the open.
European stocks and the euro were under pressure on Monday in the wake of a fresh rating agency warning on the euro zone debt crisis, while news of the death of North Korean leader Kim Jong-il sparked fears of regional instability in Asia.
Elsewhere, Oman's index ended 0.7 percent lower at 5,672 points and Kuwait's benchmark declined 0.3 percent to 5,813 points.