Pakistan has protested a US drone strike in its border area with Afghanistan which killed a top Afghan Taliban commander.
Pakistan says it was not consulted by the US ahead of the strike that killed Mullah Akhtar Mansour and regards it as an invasion of its sovereignty.
US Secretary of State John Kerry said the leaders of both Pakistan and Afghanistan were notified of the Saturday air strike but he declined to say if they were told before or after it had been carried out. He said he had spoken to Pakistani Prime Minister Nawaz Sharif by telephone.
Afghanistan's Western-backed government has repeatedly accused Pakistan of sheltering insurgents.
The death of Mullah Akhtar Mansour could trigger a battle for succession and deepen fractures that emerged in the insurgent movement after the death of its founder, Mullah Mohammad Omar, was confirmed last year, more than two years after he died.
Saturday's strike, which US officials said was authorised by President Barack Obama and included multiple drones, showed the United States was prepared to go after the Taliban leadership in Pakistan.
The United States has not confirmed Mansour's death but Afghan government chief executive Abdullah Abdullah, and the country's top intelligence agency, said he had been killed.
"Taliban leader Akhtar Mansour was killed in a drone strike... His car was attacked in Dahl Bandin," Abdullah said in a post on Twitter, referring to a district in Pakistan's Baluchistan province just over the border with Afghanistan.
Kerry said the United States had conducted a precision air strike that targeted Mansour "in a remote area of the Afghanistan-Pakistan border".
Mansour posed a "continuing, imminent threat" to US personnel and Afghans, Kerry told a news conference while on a visit to Myanmar.
"If people want to stand in the way of peace and continue to threaten and kill and blow people up, we have no recourse but to respond and I think we responded appropriately," Kerry said.
With the report of Mansour's death, attention has focused on his deputy, Sirajuddin Haqqani, leader of a notorious network blamed for most big suicide attacks in Kabul.
"Based purely on matters of hierarchy, he would be the favourite to succeed Mansour," said Michael Kugelman, a senior associate at the Woodrow Wilson Institute think-tank.
Haqqani, appointed as number two after Mansour assumed control of the Taliban last year, has generally been seen as opposed to negotiations.
Efforts to broker talks between the Afghan government and the Taliban had already stalled following a suicide attack in Kabul last month that killed 64 people and prompted President Ashraf Ghani to prioritise military operations over negotiations.
Ghani's office said on Sunday Taliban who wanted to end bloodshed should return from "alien soil" and join peace efforts.
Newshub. / Reuters