* Thai raw sugar shipments to Russia undercut Brazil
* Tight supplies underpin arabicas market
* Favourable weather augurs for ample Ivorian cocoa output
(Adds quote, updates prices)
By Sarah McFarlane and David Brough
LONDON, April 8 (Reuters) - ICE cocoa futures edged lower after Ivory Coast presidential claimant Alassane Ouattara called for an end to sanctions against the leading producer. ICE arabica coffee futures rose, supported by a weak dollar and tight supplies of high-quality beans, while sugar extended losses, with a focus on a larger-than-expected harvest in Thailand and news of bookings of Thai sugar for Russia.
In Ivory Coast, Ouattara sought to assert his grip on power after weeks of fighting that has left his rival Laurent Gbagbo isolated behind a military cordon in his bunker.
Cocoa trade has been paralysed due to the power struggle following fiercely disputed elections on Nov. 28.
Ivory Coast supplies about 40 percent of the world's cocoa. Dealers said that as cocoa trade there picked up again, the market focus would shift increasingly to fundamentals and favourable weather augured for ample production.
"Since November when we've had this risk premium the fundamentals have actually improved," a Europe-based commodity analyst at an investment fund said.
The International Cocoa Organization (ICCO) said in its latest monthly market review that the political crisis in Ivory Coast continued to instil nervousness among market participants.
"Should the dispute be resolved, significant volumes of cocoa will flow from the country after the logistical issues have been addressed," the London-based ICCO said.
"Such a development could lead to a likely decline in prices as a result of the bearish fundamental outlook of the cocoa market."
ICE July cocoa was down $34 or 1.1 percent at $2,968 a tonne in modest volume of 8,792 lots at 1437 GMT.
ICE cocoa futures prices have fallen by a fifth since hitting a 32-year high at $3,775 per tonne a month ago.
Liffe July cocoa was down 30 pounds or 1.6 percent to 1,884 pounds per tonne in slim volume of 2,847 lots.
COFFEE FIRMER
Arabica coffee futures on ICE edged higher, supported by the weakening dollar, having surged to close up 3 percent in heavy volume on Thursday as funds added positions.
The arabicas market is underpinned by tight global supplies of high quality beans.
ICE July arabica coffee rose 3.3 cents or 1.2 percent to $2.7895 per lb at 1205 GMT.
Liffe July robustas were up $17 or 0.7 percent to $2,460 a tonne in moderate turnover of 5,462 lots.
Last week's pullback in prices has stimulated buying on the physical market as roasters expand their cover, although Thursday's rebound has dampened interest, dealers said.
"There was some demand for arabica coffee when New York was trading below $2.60 a lb for June and July shipment," a European trader said.
Market technicals, based on historical prices charts, have turned bullish after Thursday's rally, dealers said.
Raw sugar futures on ICE fell, underpinned by news that Thai raw sugar shipments had been booked for Russia, undercutting traditional supplier Brazil, and signalling less congestion at Brazilian ports later this year.
ICE May raw sugar futures extended losses as the dollar dropped against a basket of currencies, falling 0.48 cent or 1.8 percent to 26.02 cents a lb at 1440 GMT.
THAI SUGAR FOR RUSSIA
Dealers focused on news of bookings of Thai sugar for Russia, undercutting traditional supplier Brazil.
Raw sugar shipments from Thailand's larger than expected crop have been booked for Russia for April loading and May arrival, European trade sources said on Friday.
Physical dealers that if Thai sugar undercut Brazilian supplies to Asian markets such as Indonesia and Malaysia, the strain on Brazilian port capacity will be less this year than last year.
"It (big Thai crop) will take pressure off Brazil, but we still think there will be congestion issues in Brazil," one European trade source said.
Dealers said the focus in the market was on how much sugar would be delivered when London's May white sugar contract goes off the board on April 15.
London May white sugar was down $3.10 or 0.4 percent to $704.60 per tonne in thin turnover of 3,710 lots. (Editing by Jason Neely)