Wildfires which killed at least 38 people and left a trail of destruction in northeastern Algeria this week have now been contained, a civil defence official told AFP on Friday.

"All of the fires have been completely brought under control," said fire brigade Colonel Farouk Achour, of the civil defence department.

Since the beginning of August, almost 150 blazes have destroyed hundreds of hectares (acres) of forest in Africa's largest country.

Algeria's forests have become the scene of hard-to-control annual summer fires as climate change exacerbates a long-running drought.

The justice ministry launched an inquiry after Interior Minister Kamel Beldjoud suggested some of this year's blazes were started deliberately, and authorities on Thursday announced four arrests of suspected arsonists.

Officials have been accused of being ill-prepared, with few firefighting aircraft available despite record casualties in last year's blazes and a cash windfall from gas exports with global energy prices soaring.

Authorities said they deployed more than 1,700 firefighters over Wednesday and Thursday to tackle the widespread blazes.

The dead included more than 10 children and a similar number of firefighters, according to multiple sources including local journalists and the fire service.

Most were in the El Tarf region near Algeria's eastern border with Tunisia, an area which was sweltering earlier this week in 48 degree Celsius (118 Fahrenheit) heat.

Among the victims were five members of the same family who perished in flames around the mountainous area of Souk Ahras.

A witness, who asked not to be named, said 12 people had burned to death in their bus as they tried to escape when fire ripped through an animal park.

Takeddine, a worker at the park who declined to give his full name, said staff had helped families with young children to escape as flames surrounded the park.

"Nobody came to help us, neither the fire service nor anyone else," he told AFP.

Fires last year killed at least 90 people and seared 100,000 hectares (247,000 acres) of forest and farmland in the country's north.

Experts have called for a major effort to bolster the firefighting capacity of Algeria, which has more than four million hectares of forest.

Algeria had agreed to buy seven firefighting aircraft from Spanish firm Plysa, but cancelled the contract following a diplomatic row over the Western Sahara in late June, according to specialist website Mena Defense.

Spain, too, has this year battled hundreds of wildfires following punishing heatwaves and long dry spells.

On Thursday, Algeria's Prime Minister Aimene Benabderrahmane defended the government's response, saying his country had ordered four new firefighting aircraft but they would not be available until December.

He added that strong winds had exacerbated the blazes and said authorities were "deploying all their means" to extinguish them.