Adds background, updates prices

LONDON, May 20 (Reuters) - New York cocoa futures on ICE turned lower on Tuesday after earlier hitting a 3-1/2 month high, while coffee prices were also slightly weaker.

COCOA

* New York cocoa CCc1 was down 1.1% to $10,858 a metric ton at 1445 GMT after setting a 3-1/2 month high of $11,280.

* Dealers said occasional setbacks were to be expected given the extent of recent gains. The market has risen about 22% so far this month.

* They noted fund buying had been the main driver of the run-up in prices although the quality of the Ivory Coast mid-crop also remained a major concern, with talk that it continues to deteriorate.

* London cocoa LCCc1 fell 0.4% to 7,624 pounds a ton.

COFFEE

* Arabica coffee KCc2 fell 0.7% to $3.6885 per lb.

* Dealers said the coffee harvest in Brazil was gaining pace, aided by favourable weather, although new crop sales are currently sluggish.

* Colombian coffee production is forecast to decrease 5.3% to 12.5 million 60-kg bags in 2025/2026 (October-September), mainly as a result of heavy rain, the U.S. Department of Agriculture's Foreign Agricultural Service said in a report.

* Robusta coffee LRCc2 fell 1.4% to $4,904 a ton.

SUGAR

* Raw sugar SBc1 gained 0.1% to 17.47 cents per lb.

* Dealers said the weather in Center-South Brazil was mostly dry, enabling the cane harvest to make good progress so far this month following rain delays during the second half of April.

* They also noted the outlook for Thailand's crop had been aided by a strong start to the monsoon season in the region.

* White sugar LSUc1 rose 0.3% to $490.80 a ton.

(Reporting by Nigel Hunt. Editing by Mark Potter)

((nigel.hunt@thomsonreuters.com; +44 (0) 7990 561421; Reuters Messaging: nigel.hunt.thomsonreuters.com@reuters.net))