Supporters of Burhanuddin Rabbani, former Afghan president and head of the government's peace council, hold a picture of him as they stand outside his house a day after he was killed in Kabul September 21, 2011.[Photo/Agencies]

KABUL - Afghans gathered to mourn assassinated former president and chief peace negotiator Burhanuddin Rabbani on Wednesday, World Peace Day, as fears mounted that his death could deepen ethnic divisions and nudge the country towards civil war.

Rabbani, perhaps the most prominent Afghan to be killed since the fall of the Taliban in 2001, died at his home on Tuesday when an insurgent he was due to hold talks with detonated explosives concealed in a turban.  

The killing was a strong statement of Taliban opposition to peace talks and the latest in a string of high-profile assassinations to shake the confidence of ordinary Afghans that security can be maintained as foreign forces withdraw.

Rabbani was Afghanistan's most influential ethnic Tajik and his killing is likely to exacerbate ethnic divides. This may do more to damage peace efforts than the loss of a negotiator who had so far produced limited evidence of steps towards talks.  

Hundreds gathered on Wednesday on the blocked-off street around Rabbani's home and armoured cars with blacked-out windows carried senior officials, friends and other prominent Afghans to a memorial service inside.

World Peace Day activities planned for across the capital, including a concert for women by famous Afghan singer Farhad Darya, were cancelled.

Rabbani's inner circle have chosen a hilltop overlooking Kabul's diplomatic enclave to bury the man who made his name as a fiery lecturer and activist and then became an anti-Soviet fighter, before briefly heading the country after the fall of the Soviet-backed regime.

"An emergency cabinet meeting today has approved the burial of Professor Rabbani on the Wazir Akbar Khan hilltop," said Waqif Hakimi, a spokesman for Jamiat Islami Afghanistan, Rabbani's political party.  

The area came under attack a week earlier when insurgents holed up in a high-rise fired rockets and gunfire towards the US Embassy and the headquarters NATO-led coalition and battled foreign and Afghan forces for 20 hours.    

Students from Kabul University gathered on a street draped with black banners close to Rabbani's home and carried signs venting their anger at the government, which they blamed for his death.

"The situation will further deteriorate because of the killings of our leaders," said Mujeed, a 21-year-old student of political law, from Rabbani's home province of Badakhshan.

"We have no choice but to arm ourselves and defend the country. This is a plot hatched by the government to get rid of Rabbani, because he was exposing the fact that the government wanted the Taliban to come back."

A group of about nine students clustered around him nodded in agreement.