US President Barack Obama on Tuesday condemned the killing of Rabbani and vowed it would not stop the United States from pressing on with its mission there.
Pakistan’s prime minister and president also condemned it.
A Pakistani government statement Tuesday said Prime Minister Yousuf Raza Gilani and President Asif Ali Zardari conveyed their “extreme anger and shock” to the Afghan government over the killing, AFP reported.
Afghan police said that a suicide bomber wearing explosives in a turban on Tuesday killed Rabbani.
“Two men were negotiating with Rabbani on behalf of the Taleban this evening — one of them had hid explosives in his turban,” said Kabul criminal investigations chief Mohammad Zaher.
"He approached Rabbani and detonated his explosives. Rabbani was martyred and four others including Massom Stanikzai were injured.”
Rabbani’s residence is in Kabul's heavily-guarded diplomatic enclave.
A police source said Stanekzai, a senior adviser to President Hamid Karzai, was badly injured in the attack. "Masoom Stanekzai is alive but badly wounded," the police source told Reuters.
One diplomat in Kabul said the death of Rabbani, head of the High Peace Council, dealt a blow to the attempts by Karzai's government to work towards a political end to the war.
"The killing of Rabbani is a serious blow against President Karzai and the government's peace and reconciliations efforts. It also underscores the inability of the government to protect even the most prominent Afghan politicians," the diplomat said.
Taleban spokesman Zabihullah Mujahid claimed responsibility for the attack outside the residence of Rabbani.
"Yes, we carried out the attack on Rabbani but will provide you other details shortly," he told Reuters.
Karzai's spokesman said the president had canceled his trip to New York for the UN General Assembly, but the US State Department said Karzai would go ahead shortly with a planned meeting with US President Barack Obama. "The president is deeply saddened learning about the death of professor Burhanuddin Rabbani and has canceled his trip to the US and will return shortly to Afghanistan," spokesman Hamed Elmi said.
Rabbani, a former leader of a powerful mujahideen party during the Soviet occupation of Afghanistan in the 1980s, was chosen by Karzai to head the High Peace Council last October.
His plan included offering amnesties and jobs to Taliban foot soldiers and asylum in third countries to leaders.
"This is a big blow to peace process and huge loss for Afghanistan," said Sadiqa Balkhi, a member of the peace council.
"Professor Rabbani was an influential and spiritual leader and was successful in luring Taleban fighters into peace process."
Rabbani served as president in the 1990s when mujahideen factions waged war for control of the country after the Soviet withdrawal.
The assassination comes a week after a 20-hour gun and grenade attack on Kabul's diplomatic enclave by insurgents, and three suicide bomb attacks on other parts of the city — together the longest-lasting and most wide-ranging assault on the city.
Last week's siege was the third major attack on the Afghan capital since June.
All three of those attacks are believed to be the work of the Haqqani network, a Taleban-allied insurgent faction, based along the Afghanistan-Pakistan border.
