|Many Afghans accuse Pakistan of backing armed groups that foment instability within their country [Reuters]
The killer of Afghan peace envoy Burhanuddin Rabbani was a Pakistani, a statement from Afghanistan's presidential palace has said, quoting investigators.
Evidence shows that the former president's death last month "was plotted in Quetta and the person who carried out the suicide attack against Rabbani was a citizen of Pakistan," the statement released on Sunday said.
It added that the killer had been living in Chaman, a Pakistani border town near Quetta.
Rabbani, who was appointed by Afghan President Hamid Karzai as the chairman of a council tasked with negotiating with the Taliban, was killed by a suicide bomber at his home in Kabul on September 20.
Rabbani had thought he was meeting a representative carrying a special message from the Taliban.
Karzai's government has been struggling to start talks with the Taliban in a bid to end the 10-year conflict since a US-led invasion toppled the group from power, but has made no meaningful progress.
Hundreds of Afghans took to the streets of the Afghan capital, Kabul, on Sunday to condemn the recent shelling of border towns by Pakistan's army and accuse its powerful spy agency of involvement in the killing of Rabbani.
Sunday's protest came amid heightened tensions between the neighbours, with Afghan officials blaming Pakistan's Inter-Services Intelligence (ISI) and the Taliban's senior leadership over Rabbani's assassination.
Angry protesters, gathered under tight security, chanted "Death to Pakistan" and "Death to ISI".
"Pakistan and its ISI must stop interfering in Afghanistan. Our patience is running out," said Daoud Kodamani, a 22-year-old university student.
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"Fighting our country's enemies is nothing new for Afghans and Pakistan is another enemy to fight with," he said.
Many Afghans have long accused Pakistan and the ISI of backing armed groups to further Islamabad's own interests, which Pakistan denies.
Afghan provincial officials say Pakistan's military last month fired hundreds of rockets in eastern Kunar and Nuristan provinces, which share a long border with lawless tribal areas inside Pakistan.
Although the shelling did not cause significant casualties, it followed more than a month of bombardments by Pakistan's military in June and July that Afghanistan said had killed at least 42 people.
Pakistan has repeatedly blamed Afghanistan for allowing armed groups to find refuge on its side of the border.
A spokesman for Karzai meanwhile said the Afghan president was reviewing his strategy for making peace with the Taliban and would reveal the next steps "very soon".
"All peace talks with the Taliban are suspended," said Siamak Herawi on Sunday. "The president will review the peace and reconciliation strategy."
Jalal Rabbani, son of Burhanuddin Rabbani, told Al Jazeera that the Taliban were "enemies of peace and we will not be sitting with them when they don't discuss peace".
On Friday, Karzai expressed frustration with senior Afghan Taliban chiefs and stressed the need to hold discussions with Pakistan to ensure security.
"If [the Pakistanis] would like to see peace in Afghanistan, it is within their reach; and right now the world needs to convince them that the only way to proceed in Afghanistan is through peaceful manners," said Rabbani.
He also accused Pakistan of playing "double games" and purposely providing Afghans with false intelligence about armed groups.