KABUL: Former Afghan President Burhanuddin Rabbani and head of the council tasked with trying to negotiate a political end to the war was killed at his home on Tuesday in what one diplomat called a major blow to the government's peace efforts.   

Coming just a week after a 20-hour siege by militants in the capital, it was the highest profile killing in Afghanistan since the younger half-brother of President Hamid Karzai, Ahmad Wali Karzai, was killed at his home in July by a highly trusted family security guard.    

"Rabbani has been martyred," Mohammed Zahir, head of the Criminal Investigation Department of the Kabul Police, told Reuters. He had no further details.   

His residence is in Kabul's heavily guarded diplomatic enclave.

Advisor wounded

A police source said Masoom Stanekzai, a senior adviser to President Hamid Karzai, was badly injured in the attack.   

"Masoom Stanekzai is alive but badly wounded," the police source, who asked not to be named as he is not authorised to talk to the media said.

One senior 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.

Taliban claims responsibility

Taliban spokesman Zabihullah Mujahid claimed responsibility for the attack outside the residence of former Afghan president Burhanuddin Rabbani.

"Yes, we carried out the attack on Rabbani but will provide you other details shortly," he said.   

Karzai's spokesman said the president had cancelled 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.   

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 Taliban 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 Taliban-allied insurgent faction, based along the Afghanistan-Pakistan border. 

Obama, Karzai say undeterred by killing
US President Barack Obama on Tuesday condemned the killing of the head of Afghanistan's High Peace Council, former President Burhanuddin Rabbani, and vowed it would not stop the United States from pressing on with its mission there.

Afghan President Hamid Karzai, at the start of talks with Obama on the sidelines of the UN General Assembly, said Rabbani's death "will not deter us" from continuing the quest for peace.