The founder of the Haqqani network, one of Afghanistan's most effective and feared militant groups, has died after a long illness, their affiliates the Afghan Taliban announced Tuesday.

Jalaluddin Haqqani, whose son Sirajuddin now heads the brutal group and is also the Taliban's deputy leader, died "after a long battle with illness", the Taliban said in a statement.

Jalaluddin "was from among the great distinguished Jihadi personalities of this era", the Taliban said in a statement posted on Twitter.

During the 1980s the Haqqani figurehead was an Afghan mujahideen commander fighting the Soviet occupation of Afghanistan with the help of the United States (US) and Pakistan.

He gained notoriety for his organisation and bravery, garnering attention from the CIA and a personal visit from US congressman Charlie Wilson.

A fluent Arabic speaker, Jalaluddin also fostered close ties with Arab jihadists, including Osama Bin Laden, who flocked to the region during the war.

Later, Jalaluddin became a minister in the Taliban regime.

It was not clear when or where Jalaluddin died or what illness he had. In 2008 and 2015 there were rumours of his death. He was believed to be in his early eighties. Unverified reports have placed him in Pakistan in recent years.

Given the already leading role played by his son, it is not clear what Jalaluddin's demise will mean for the extremist group.

Devastating attacks

The Haqqani network has been blamed for spectacular attacks across Afghanistan since the US invasion.

It is also widely believed to have been behind many of the recent attacks in the capital Kabul that were claimed by the local wing of the militant Islamic State (IS) group.

Analysts believe it works with IS ─ which at the same time is involved in a turf war with the Taliban ─ to avoid blame and political blow back.

Designated a terrorist group by the US, the Haqqanis are known for their heavy use of suicide bombers.

They were blamed for the devastating truck bomb in the heart of Kabul in May 2017 that killed around 150 people ─ though Sirajuddin later denied the accusation in a rare audio message.

The network has also been accused of assassinating top Afghan officials and holding kidnapped Westerners for ransom.

They include the Canadian Joshua Boyle, his American wife Caitlan Coleman, and their three children ─ all born in captivity ─ who were released last year, as well as US soldier Bowe Bergdahl, who was freed in 2014. Analysts and diplomats downplayed the significance of his death for the group's operations.

Analyst Michael Kugelman of the Wilson Center in Washington tweeted: "Given how long he'd been ill, his death won't have a big impact on the war."

"His death is not going to affect the network or Taliban operations because he was not an active member," Afghan political analyst Atta Noori told AFP. "He was too old, sick and in bed for years."