An oil spill off Ireland's coast that occurred near Russian warships is spreading towards Britain, Reuters quoted the Irish coastguard as saying today. The British Coastguard said up to 1,000 tonnes of fuel oil might have spilled but an Irish estimate yesterday put the figure at 300 tonnes. Russia said the size had been exaggerated. Irish, British and Russian warships were on the scene. The slick was breaking up and spreading over a larger area, Ireland's Transport Department said. Interfax news agency quoted the Russian armed forces head of general staff, Nikolai Makarov, as saying on Tuesday that no large leak of fuel occurred during a refuelling operation between Russian ships in the area.