Blazes raged across northern Algeria on Thursday as the country observed a national day of mourning for dozens of people killed in the latest wildfires to sweep the Mediterranean.

The North African country has been in the grip of devastating fires since Monday that have claimed at least 69 lives -- 41 civilians and 28 soldiers.

Soldiers and civilian volunteers have joined firefighters on multiple fronts in the effort to extinguish the blazes that have been fanned by windy and tinder-dry conditions.

In Tizi Ouzou district, the area with the highest casualty toll, an AFP journalist reported entire sectors of forest going up in smoke.

Villagers forced to evacuate in order to escape the flames began trickling back to their homes, overwhelmed by the scale of the damage.

"I have nothing left. My workshop, my car, my flat. Even the tiles were destroyed," one of them told AFP.

But he said he had "managed to save his family", while adding that "neighbours died or lost their relatives". 

'Surge of solidarity'  

Flags were flying at half-mast after President Abdelmadjid Tebboune declared three days of national mourning starting from Thursday.

Algerian authorities say they suspect widespread arson after so many fires erupted in such a short space of time.

The country's state prosecutor on Thursday ordered an investigation after a mob allegedly lynched a man they accused of sparking the wildfires.

Video footage posted online Wednesday showed a crowd beating to death 38-year-old Jamal Ben Ismail and setting him ablaze in the Tizi Ouzou district.

On the fourth day of the wildfires, efforts to overcome the blazes are continuing in many regions where civilians and soldiers often with limited means joined the fight.

Images of trapped villagers, terrified livestock and forested hillsides reduced to blackened stumps have been shared on social media.

Algeria is also chartering two firefighting planes from the European Union.

France also announced the arrival in Algeria of two Canadair firefighting planes it has sent.

"They will help the rescue efforts to deal with the terrible fires," French President Emmanuel Macron tweeted.

Neighbouring Morocco, with whom Algeria has long had strained ties over the Western Sahara, also offered to help by providing two planes.

Faced with the scale of the disaster, pleas for assistance are multiplying in Algeria and beyond.

"Individuals and associations are mobilising... by organising collections of clothes, foodstuffs, medicines and hygiene products," said Algeria's TSA news website, calling it a "surge of solidarity".

Djaffar, a resident of the village of Agoulmim in Kabylie, expressed his gratitude on Berber TV.

"God bless them... We had no electricity and people brought in generators from all around," the exhausted villager said after his ordeal.

"The flames were so high, they destroyed everything. Suddenly it was like a volcano," he said. 

Heatwave -

High winds fuelled the rapid spread of the flames in tinder-dry conditions created by a heatwave across North Africa and the wider Mediterranean.

The authorities have raised the possibility of criminal behaviour.

Four suspected "arsonists" were arrested so far, but their identities or suspected motives have not yet been disclosed.

Armed forces chief Said Chengriha visited soldiers in Tizi Ouzou and Bejaia, another badly affected area. Prime Minister Aimene Benabderrahmane also visited Tizi Ouzou.

Each summer, Algeria endures seasonal wildfires, but rarely anything approaching this year's disaster.

Meteorologists expect the Maghreb heatwave to continue until the end of the week, with temperatures in Algeria reaching 50 degrees Celsius .

Across the border in Tunisia, where almost 30 fires have been recorded since Monday, the mercury hit an all-time record of 50.3 Celsius in the central region of Kairouan (centre).

Almost 30 fires have been recorded in Tunisia since Monday.

On the northern shores of the Mediterranean, deadly wildfires have been raging in Turkey and Greece for the past two weeks.

In Italy, where firefighters were battling more than 500 blazes overnight, Sicily recorded a temperature of 48.8 degrees Celsius  on Wednesday that is believed to be a new European record.