A police helicopter has sighted arsonists lighting new fires on moorland even though a huge moor fire is still raging nearby.
22 fire engines are still at the scene at Winter Hill in Lancashire. It's been declared a major incident after merging with another blaze.
Meanwhile firefighters are also facing a second major fire at Saddleworth Moor.
Manchester Fire Assistant Chief Dave Keelan told ITV News that crews are facing challenging enough conditions - and that the fact that people would deliberately set more fires is "devastating"
Firefighters have been facing exhausting heat as they tackle the fire line - and have asked for donations of water, socks and other supplies.
They've also warned that some people have been putting themselves and others at risk by going to look at the blaze.
People are being asked to stay away, not block roads needed for emergency vehicles, and to not fly drones in the area.