Off duty firefighters from the Tyne and Wear area are helping to battle a blaze on moors in Yorkshire.
Police investigating the cause of a large fire on Yorkshire's famous Ilkley Moor have arrested three men amid suggestions the blaze could have been deliberate.
A helicopter was brought in on Sunday to drop tonnes of water onto the smouldering moorland just to the south of the town of Ilkley, West Yorkshire.
More than 100 firefighters tackled the fire in sweltering conditions at its height on Saturday afternoon.
The 14 crews mobilised from across West and North Yorkshire withdrew overnight but around 70 firefighters returned to the moor on Sunday morning.
The helicopter was seen scooping water from a small nearby reservoir and dropping it on the scorched ground.
The blaze is not far from the Cow and Calf rocks, which are the focal point of one of the most popular recreation areas in the region.
In a statement on its Facebook page Tyne and Wear Fire and Rescue Service said: "We are currently waiting for some of our dedicated off duty firefighters to attend for duty to assist @WYFRS tackle a #Wildfire on Ilkley and Marsden Moors #FireFamily #StaySafe."
Police and Bradford Council have warned the public to stay away from the area as firefighting operations continued.
In a statement issued on Sunday, West Yorkshire police confirmed that arrests had been made in relation to the fire.
It said: "West Yorkshire Police can confirm that three men have been arrested in connection with a fire on Ilkley Moor yesterday.
"The men, who are aged 19, 23 and 24, remain in custody at this time and enquiries are ongoing with the fire service to establish if this incident is linked to the larger blaze.
"The fire service are continuing to tackle the blaze and members of the public are advised to avoid the area.
"The blaze is believed to now be under control, but we would like to remind members of the public that this recent hot weather may have made some moorland areas tinder dry, which means that even small fires may spread rapidly in these conditions."
Local police sergeant Terri Green said on Twitter: "Please stay away from Ilkley Moor today.
"Deploying many officers to cordon it off due to dangerous conditions due to the fire. Going to need plenty of water and sun cream today for my team and I."
West Yorkshire Fire Service said on Sunday morning that 12 crews remained on the moor using water jets and beaters.
A spokesman said: "Specialist wildfire units are also in attendance and a helicopter will be assisting with overhead water attack."
The service said crews also had to cope with another moor fire, a few miles further south, involving 50 acres of land near The Dick Hudsons Pub, above Shipley.