Afghanistan on Wednesday cancelled a planned army visit to Pakistan to protest against alleged cross border shelling, the latest sign of deteriorating relations between the troubled neighbours.
The Pakistani army invited 11 Afghan officers to take part in a military exercise and drill in the southwestern city of Quetta, the Afghan foreign ministry said.
"This visit will no longer take place due to the resumption of unacceptable Pakistani artillery shelling against different parts of Kunar province," it said.
Kunar provincial governor Fazlulah Wahidi told AFP that up to 50 rockets, fired from the Pakistani side of the border, landed in two districts on Monday and Tuesday, damaging property.
A Pakistani military official told AFP it had "no details" of the cancellation and declined to give any other immediate response.
Afghanistan and Pakistan are deeply distrustful of each other and trade blame for Taliban violence plaguing both sides of their 2,400-kilometre (1,500-mile) border, known as the Durrand Line, drawn up by British colonialists.
Relations had recently improved, building up to a three-way summit hosted by British Prime Minister David Cameron on February 4 as part of efforts to end 11 years of war in Afghanistan.
Western officials believe that Pakistan, which backed Afghanistan's 1996-2001 Taliban regime, has a crucial role to play in shoring up peace efforts between Kabul and Taliban insurgents.
But since the London talks, there have been a series of public accusations and fallings-out between Afghan and Pakistani officials.
In a report released on Tuesday, Pakistan's ISI intelligence agency said there was "strong support" in Afghanistan for members of the Pakistani Taliban, which have been fighting against Islamabad for nearly six years.
Submitted to the Supreme Court as part of a long-running investigation into how the ISI holds terror suspects, the agency wrote of a "nexus" between members of the Pakistani Taliban and the Afghan government.
"The strong support of miscreants, through provision of logistics, training and finances by the anti-Pakistan elements, specially from across the border, is one of the main factors for increased militancy," the ISI said in English.
Last month, a conference of Afghan and Pakistani religious scholars aimed at pushing forward the peace process was called off due to disagreements.
The head of Pakistan's Ulema Council, Allama Tahir Ashrafi, said there was no point to the meeting unless the Afghan Taliban were invited.
He was then accused in Afghanistan of condoning suicide attacks in a television interview, in which he insists he was misunderstood. His public opposition against suicide attacks is well documented.
There was another spat over Maulvi Faqir Mohammad, a senior Pakistani Taliban fighter arrested recently in Afghanistan. Pakistan demanded he be handed over, but Kabul indicated he would be held as a bargaining chip for prisoner exchanges.
Pakistan has released at least 26 Afghan Taliban prisoners in recent months -- a move that Kabul welcomed in the hope that they could help persuade the Taliban to enter into peace talks.
But there is little evidence that the prisoners have done so and Kabul is now increasingly impatient that other detainees, including former Afghan Taliban deputy leader Abdul Ghani Baradar, have not been handed over.
"In recent months unfortunately, Pakistan's commitments, specially very strong commitments made during London talks were not fulfilled and we missed some good months," Afghan foreign ministry spokesman Siamak Herawi told AFP recently.
A senior Pakistani security official was quick to hit back.
"The overall effort seems to be to sabotage the peace talks and not let Pakistan get close to the driving seat," he told AFP on condition of anonymity.
Britain's Cameron held a telephone conversation with Afghan President Hamid Karzai Wednesday evening to follow up on the London talks and discuss Afghanistan's relations with Pakistan, according to an official statement that did not elaborate further.