Once close allies, relations between Pakistan and Afghanistan have soured dramatically — with experts blaming a colonial-era border and a backfired strategy of supporting religious extremists.
Pakistan last week conducted deadly aerial strikes on Afghanistan's Paktika province, reportedly killing 46 people, including women and children.
The strikes were purportedly aimed at Tehrik-i-Taliban Pakistan (TTP) militants — who aim to overthrow Pakistan's government and establish an Islamic state — operating from Afghan territory.
Afghanistan's Taliban government condemned the incident, describing it as a "blatant violation of all international principles", and launched retaliatory attacks.
The Taliban Defense Ministry, posted on X, saying its forces targeted Pakistani points that "served as centres and hideouts for malicious elements and their supporters who organised and coordinated attacks in Afghanistan" without elaborating further.
A pro-Taliban media outlet, Hurriyet Daily News, cited ministry sources as saying that the strikes killed 19 Pakistani troops and three Afghan civilians.
Afghanistan also summoned the chargé d'affaires of the embassy of Pakistan in Kabul to deliver a strong protest note regarding the air strikes.
Now Pakistan faces a major diplomatic headache with a key ally amidst its own internal political crisis and ailing economy, a problem experts warn the country cannot afford.
Historical roots of the tensions
The origins of the discord trace back to the Durand Line, a colonial-era border established in 1893 that successive Afghan governments have refused to recognise.
"The main issue has been the border tensions, exacerbated by the Taliban's resurgence and their refusal to act against the TTP," said Nematullah Bizhan, a senior lecturer at the Australian National University's Development Policy Centre.
[durand line image]Dr Bizhan said Pakistan had long promoted religious extremism to counter Afghan nationalism.
"During the Soviet invasion of Afghanistan in the 1980s, Pakistan established religious schools to train young Afghan refugees as fighters, ensuring influence over Afghanistan," he said.
"Pakistan's establishment has always sought a friendly or pro-Pakistan government in Kabul to secure its western borders."
However, this strategy has backfired in recent decades, as extremist religious groups like the TTP turned their focus to Pakistan.
Escalating conflict
Abdul Basit, a senior associate fellow at RSIS in Singapore, said Pakistan and TTP had established fragile ceasefires in 2021 and 2022.
"Both collapsed due to a lack of trust and ideological differences," Mr Basit said.
"These short-lived truces reflect the complexity of the TTP issue, which intertwines with ethnic grievances and Islamist narratives."
Mr Basit said that "the TTP has blended ethnic Pashtun nationalism with Islamist ideology, presenting itself as a champion of Pashtun rights while exploiting grievances over the border and governance issues".
In July last year, Pakistan's Defence Minister, Khawaja Asif, told the BBC his country would continue to launch attacks against Afghanistan as part of a new military operation aimed at countering terrorism.
"It's correct that we have been carrying out operations in Afghanistan, and we will continue to do so," Mr Asif told BBC Urdu.
"We won't serve them with cake and pastries. If attacked, we'll attack back."
With advanced weaponry left behind by the US in Afghanistan, the TTP had significantly increased its operational capabilities, said Mr Basit.
"The group [TTP] now has long-range sniper rifles and night-vision goggles, which have raised casualty counts among Pakistani forces guarding the border," he said.
Pakistani security forces in 2024 suffered the highest casualties in nearly a decade while battling insurgency, the Islamabad-based Center for Research and Security Studies said in a report.
According to the report, Pakistani forces killed 950 militants this year, while 527 Pakistani security forces and 489 civilians were killed in militant attacks.
Pakistan's attempts to fortify the Durand Line with a physical fence have also faced significant challenges with breaches frequent.
"Erecting a physical border over thousands of kilometres is an over-simplistic solution to a deeply complex problem," said Mr Basit.
"Tribes living on both sides feel alienated, and actors like the TTP exploit these grievances."
Pakistan's miscalculation
Experts say that Pakistan miscalculated the potential benefits of the Taliban's return to power in Kabul.
Islamabad had hoped that the Taliban would curb the TTP's activities, take back the thousands of Afghan refugees living in Pakistan, and neutralise anti-Pakistan elements in Afghanistan, said Mr Basit.
"Pakistan simplistically assumed that all problems would vanish with the Taliban in power. But every major issue — refugees, border disputes, militancy — has instead been exacerbated," he said.
"Pakistan is now paying the price for its decades-long investment in extremist groups.
"It finds itself in a position where it must manage tensions with the Taliban while confronting the TTP's growing threat."
As relations deteriorate, the two governments face immense pressure to maintain dialogue while addressing security concerns.
"The relationship is at its lowest ebb, but it is unlikely to collapse completely," Mr Basit said.
"The current pattern of violence, air strikes, and retaliatory attacks will likely continue, with occasional diplomatic overtures."
Pakistan's domestic challenges
Mr Basit said Pakistan's military was overstretched, by TTP militancy, a separate insurgency in Balochistan, and political turmoil stemming from overthrow of former prime minister Imran Khan.
"While Pakistan's economy has stabilised somewhat under an IMF program, these internal and external pressures strain its ability to manage security and diplomacy effectively," he said.
He said the need for pragmatic solutions over idealistic expectations should be at the forefront of Pakistan's strategy.
"Fundamental discussions are required to manage tensions rather than resolve them outright," he said, citing the Taliban government's lack of international legitimacy as a major hurdle.
"Pakistan must balance kinetic actions with diplomacy, but there are no easy answers.
"The border issue and the TTP challenge will remain irritants for the foreseeable future."
ABC/wires
