Another whale may be in trouble in shallow waters off the British coast, rescuers have said.
The latest report comes after a bull died at Hunstanton, Norfolk, on Thursday. This was the 30th sperm whale death in the North Sea this year.
British Divers Marine Life Rescue (BDMLR) said on Tuesday that it was investigating the latest sighting off north Norfolk.
A spokeswoman said the sighting had been referred to them but there were no further details on precise location or species.
Last week's whale death followed the discovery of four dead whales washed up on the Lincolnshire coast and another at Hunstanton last month.
Others have been found in France, the Netherlands and Germany.
The Cetacean Strandings Investigation Programme, which examines all whale, dolphin and porpoise strandings in the UK, is working to establish why the whales came ashore and how they died.
This could help establish what the whales, thought to have come from the same bachelor pod normally living off the west coast of Norway, were doing in the North Sea.
One theory is that the male whales could have taken a wrong turn while heading south to find females or been lured by food.
Stephen Marsh, operations manager at the BDMLR, said: "At the moment the report from the coastguard is that the whale is still free-swimming.
"Because we're come up to spring tide, the waters may be a bit deeper but that can be a double-edged sword because you get very high high tides and very low low tides.
"If it does strand the story will be very similar to what we've had recently - the whale will have very little chance of relaunching and, if it does, its chances of survival will be very low."