Three men have been arrested as firefighters continued to battle the blaze that has swept across Ilkley Moor in West Yorkshire, police said on Sunday.

The men, aged 19, 23, and 24, were in custody over a smaller fire as police investigated whether there was any link to the larger blaze. More than 70 firefighters were at the scene, south of the town of Ilkley, with a helicopter also being deployed after several acres of the moor caught fire on Saturday – the hottest day of the year.

In a statement confirming the arrests, West Yorkshire police also said that the fire is “believed to now be under control” and reminded the public: “this recent hot weather may have made some moorland areas tinder dry, which means that even small fires may spread rapidly in these conditions.”

That came after West Yorkshire fire service said on Sunday morning that a helicopter had been brought in to help fight the blaze along with 12 crews using water jets and beaters.

Sunrise on Ilkley Moor as the fires continued to burn. Photograph: Simon Wilkinson/SWpix.com/Rex/Shutterstock

Police urged people to stay away from the moor on Sunday, in what would be one of the town’s busiest days of the year so far with temperatures expected to reach 22C.

Ilkley Moor is famous both for its picturesque moorland walks and Cow and Calf rocks, and also for inspiring Yorkshire’s unofficial “national anthem”, On Ilkla Moor Baht ’At.

Sgt Terri Green, from West Yorkshire police, 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.”

Footage showed firefighters attempting to beat down a long and rapidly growing wall of flames on Saturday evening.

On Saturday night, Martyn Hughes, a watch manager at North Yorkshire fire and rescue service, which is assisting the West Yorkshire service, tweeted: “The intense heat, steep slopes and rough terrain are causing the fire to spread rapidly whilst we try to get near the flames.”

Dave Walton, the deputy chief fire officer of West Yorkshire fire and rescue service, said his crews would spend much of Easter Sunday on Ilkley Moor. “It’s going to be warm and conditions are tough. Our crews, @ WYFRSControl staff, officers and support staff will be part of the team effort,” he said.

The Labour party leader, Jeremy Corbyn, said the “awful scenes” on the moor were a reminder “of why we urgently need to tackle climate change”.