DUBAI, March 30 (Reuters) - Kuwait's stock market underperformed in an otherwise quiet region during early trade on Thursday as three Kuwaiti large-cap shares went ex-dividend.

The Kuwaiti index dropped 1.9 percent because of a 4.4 percent drop in Ahli United Bank , a 3.3 percent decline in Kuwait Telecom and a 1.5 percent fall in Burgan Bank . Most other stocks also fell with Boubyan Bank down 2.4 percent.

Meanwhile Riyadh's index was up 0.3 percent in the first half-hour as most petrochemical shares rose. National Industrialization (Tasnee) added 1.8 percent.

Yanbu National Petrochemical , however, dropped 1.7 percent after saying it planned a temporary shutdown at two of its facilities. The financial impact was estimated to be 110 million riyals ($29.3 million) and would be reflected in second- and third-quarter results, it added.

Saudi British Bank was the top-performing blue chip, rising 2.7 percent.

Dubai's index barely moved, with declining shares outnumbering advancing ones 21 to eight. Aramex lost 2.8 percent as it went ex-dividend.

Builder Drake & Scull fell 1.4 percent after saying it had breached financial covenants in relation to a sukuk syndicated facility and other bank facilities in 2016 after having incurred losses last year.

In Qatar, the index was flat but drilling rig provider Gulf International Services added 1.6 percent.

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