A firefighting airplane provided by Iran is expected to start aiding in efforts to extinguish the forest fire which has been raging since days in Balochistan's Koh-i-Suleman range, Forest Officer Ateeq Karar said on Monday.

A spokesperson for the Iranian consulate in Quetta said that the plane, Ilyushin 76, is the "biggest firefighter aircraft" in the world and would land at Rawalpindi's Nur Khan Airbase today.

The airplane would remain in Pakistan till the fire has been extinguished, the spokesperson added.

The fire in the Shirani forest started a week ago after the area was struck by lightning and has since engulfed hundreds of trees dotting the mountain range, home to the world's largest pine nuts (chilghoza) forest and connecting Balochistan, Punjab and Khyber Pakhtunkhwa provinces.

It has now turned into a raging inferno, forcing several residents of nearby villages to move to safer locations. Different species of animals and birds are also under threat.

The army, provincial and federal disaster management authorities and other departments are struggling to douse the flames. Three people have lost their lives so far while three others have been badly injured.

Read: Rain is biggest hope — Operation on as Shirani forest fire continues to rage in Koh-i-Suleman range

The blaze continues to rage in an area spanning 20 kilometres in Shara Gulghai and 15km in Toorghardana, Forest Officer Kakar said.

Zhob Commissioner Bashir Ahmed Bazai also confirmed to Dawn.com that the fire had spread over a 25-35 kilometre-radius.

"Pine trees dating back more than 1,000-1,500 years are located in the forest. A pine tree starts giving fruit after 25 years. These [areas] are part of the world's largest pine forest," Kakar said.

The fire is expected to have damaged a large number of trees. The final tally of burnt trees will be confirmed after the fire has been extinguished, allowing officials to conduct a survey.

Meanwhile, Balochistan Chief Minister Mir Abdul Qudoos Bizenjo said that the provincial government had stepped up efforts to douse the fire.

In a statement, he said all resources were being utilised and the federal government was also fully cooperating on Prime Minister Shehbaz Sharif's instructions.

The Balochistan government had started relief work since the day the fire began, he said, adding that Pakistan Army was helping in battling the blaze.

"Chemicals and water are being sprayed via helicopters," he further said.

The chief minister lamented the "large-scale damage" and said he was grieved at the loss of livelihood associated with the Shirani forest.

The government would not abandon its people at a difficult time, he assured.

Bizenjo earlier announced Rs1 million each for the families of three people who lost their lives and Rs500,000 for each injured. He said the federal government would also announce compensation for the fire victims.

"Fire is mostly on mountain tops (10,000 feet high) away from population centres but continues to spread due to hot weather, inaccessible nature of the terrain and dry winds; nearest village is approximately eight to 10km away from the location of the fire," the Inter-Services Public Relations (ISPR) said in a statement last week.

A Frontier Corps wing and two army helicopters, along with local administration and Levies have been employed in firefighting and relief efforts.

One helicopter was being used to drop water and another to drop fireball and fire extinguishing chemicals to put out the fire.

As many as 400 fireballs, 200 fire suits, blankets, tents, mats and fire extinguishing equipment were provided by National Disaster Management Authority through FC Balochistan.

Last week, Prime Minister Shehbaz ordered authorities to take urgent steps to control the fire.