Mynydd Mawr fire: Helicopter brought in to help tackle large blaze

Fire crews hope a helicopter will help put out a blaze that covered an area of 100,000 sq m at one stage.

It is the second fire of its size to have broken out in Gwynedd over the past few days.

The fire service said Mynydd Mawr had been "quite devastated" by the fire.

Elsewhere, two men from Rhymney and Nelson in Caerphilly county, aged 24 and 23, have been arrested on suspicion of arson and burglary. Both men have been released on bail.

That followed a fire at the Heads of the Valleys industrial estate in Rhymney at around 01:40 GMT on Saturday, 19 March.

Geoff Hall, of North Wales Fire and Rescue Service, said the cause of the Mynydd Mawr fire was unclear, but warned people against carrying out controlled burns on land because of the risks of them spreading.

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"You need a burn plan in place. Unless you can actually tackle this fire yourself, with your burn plan that you have created, we shouldn't be doing any burns that we can't deal with," he told BBC Radio Wales Breakfast.

"It places a tremendous strain on the resources."

Landowners and farmers were warned about the dangers of controlled burns

The current blaze near Y Fron village, near Caernarfon, covered an area of 100,000 sq m on Wednesday, but four appliances and a specialist wildfire unit have been tackling it.

A helicopter from south Wales has also travelled up to help by dropping water on the fire, with crews then ready to follow up on foot.

Fires broke out over a wide area in Gwynedd

It is hoped it will be out later today.

"The season we're in, we do have people trying to do controlled burns, which all too often result in uncontrolled burns, which cost us and the taxpayers hundreds of thousands of pounds, as well as the health and safety of the crews who are at stake whilst we're dealing with these," Mr Hall added.

North Wales Fire and Rescue Service said crews were also tackling fires at Rhiw, near Llanbedr in Gwynedd, and in Wrexham.

Incidents in Clynnog Fawr and Penygroes were also dealt with in Gwynedd, while a fire at Pant Glas is ongoing.

Fire crews from elsewhere in Wales have also been tackling a number of fires, including in the Preseli Hills, Pembrokeshire, Ammanford in Carmarthenshire and near Crickhowell in Powys.

These are the latest in a series of blazes since a spell of warm, dry weather begun last weekend.

Youths on motorbikes were blamed for starting some and driving off, with fire bosses saying most blazes are started deliberately.

At the scene: Matt Richards, BBC Wales reporter

Firefighters have been tackling blazes across Wales - with a number in Gwynedd over the past few days

Firefighters were already dealing with one large grass blaze above Fron on Wednesday when another spread quickly on the other side of the valley.

Hundreds of thousands of square metres of gorse could be seen going up in smoke.

A helicopter made continual trips to nearby lakes for water to douse the flames as crews, dwarfed by the mountain, tackled them up close.

It's not clear yet what started the inferno but landowners have been asked to ensure controlled burning was done carefully.

To nearby residents' relief, crews returned at dawn on Thursday to continue battling the blaze.

As it raged through the night, its glow created an unsettling, eerie focal point.

The weather has exacerbated fires across Wales.

Emergency crews know this may be the start of a busy season.

Deliberate or accidental, fires started during dry periods can quickly get out of hand.