There are reports of birds being washed up on the Flamborough coast following a North sea oil spillage.
Yorkshire Wildlife Trust says guillemots and black-headed gulls have been hit by the spill.
The spill happened off the North Yorkshire coast and the clean-up is being organised by Scarborough Borough Council.
Andy Skelton, Scarborough Borough Council's Head of Environmental Services said:
"We are currently in the process of clean up operations on a 15 mile stretch of our coastline between Scarborough and Speeton after deposits of oil were washed up onto beaches late yesterday afternoon and overnight.
"At this time, it is not known where the oil has come from but the strong easterly winds and heavy sea conditions are thought to have assisted the oil's journey to the shoreline.
"The Maritime and Coastguard Agency has been trying to determine the source of the pollution, including conducting a surveillance flight, and together with the Environment Agency, is arranging for samples of the substance to be tested.
"We have had reports of a small number of dead seabirds being found. We have ensured the RSPB and RSPCA are aware of the problem."
