Hundreds of Afghans gathered Wednesday to protest the killing of former Afghan president and peace negotiator Burhanuddin Rabbani at his home in the capital Kabul.

Police say Mr. Rabbani, who served as president from 1992 to 1996, was killed Tuesday by a suicide attacker who detonated a bomb hidden in his turban. Officials say the attacker had claimed to be an emissary from the Taliban carrying a special message and met Mr. Rabbani in his home.

At least four other people were killed in the blast, and one of President Hamid Karzai's key advisors, Masoom Stanekzai, was wounded.

Mr. Rabbani headed the country's High Peace Council and was in contact with elements of the insurgency in order to find a peaceful political settlement to the conflict.

On Wednesday, crowds of mourners carrying pictures of Mr. Rabbani and banners gathered on a street outside of his house, while a string of government officials arrived to pay their respects amid tight security. Mr. Rabbani's funeral is expected to be held in Kabul sometime this week.

NATO officials blamed two suicide bombers for the attack, saying they were feigning a desire to conduct reconciliation talks. A Taliban spokesman told Reuters news agency on Tuesday that the group carried out the attack and had appointed two articulate and well-trained fighters to build contacts with Mr. Rabbani.

But another reported Taliban spokesman rejected that claim, telling the French news agency on Wednesday that the group would not comment about the attack.

Mr, Karzai condemned the assassination Tuesday saying the former Afghan president sacrificed his life for the sake of Afghanistan and peace. President Karzai was set to address the United Nations General Assembly in New York on Wednesday, but he cut short his U.S. trip and returned to Afghanistan following Tuesday's attack.

U.N. Secretary-General Ban Ki-moon condemned Mr. Rabbani's assassination “in the strongest possible terms.” He said the U.N. remains committed to supporting Afghanistan and its people in attaining peace and stability and to working in close cooperation with them.

In other violence, at least 10 policemen were killed in a bomb attack in southern Ghazni province late Tuesday.

Officials say the police chief for Waghaz District was killed in the attack, which occurred as police were conducting a search operation for militants in an area building.

Also in the south, NATO says two of its service members were killed in an insurgent attack. No further details were released.