KABUL - Ahmad Wali Karzai, a brother of Afghan President Hamid Karzai and one of the most powerful but controversial men in southern Afghanistan, was shot dead at his home on Tuesday.

Here are some key quotes on his death:
President Hamid Karzai:
"My younger brother was martyred in his house today. This is the life of all Afghan people. I hope these miseries which every Afghan family faces will one day end."

Syed Yousuf Raza Gilani, Pakistani Prime Minister:
Killing of Ahmad Wali Karzai is "an act of cowardice," and we express our "heartfelt condolences" and prayed for peace for Wali Karzai and strength to his family.

Dr. Manmohan Singh, Indian Prime Minister:
On the behalf of the People and government of India and on my own behalf, please accept my heartfelt condolences on this irreparable loss. Apart from your personal bereavement, the people of Afghanistan have lost a prominent public figure. In this difficult hour, our thoughts and prayers are with you, your family and the people of Afghanistan.

Gen. David Petraeus, The Commander of U.S. and NATO Forces in Afghanistan:
"President Karzai is working to create a stronger, more secure Afghanistan, and for such a tragic event to happen to someone within his own family is unfathomable. I strongly condemn the actions by anyone who played a role in this murder. ISAF will support the Afghan government in every possible way to bring to justice those involved in the murder of Ahmad Wali Karzai."

Karl W. Eikenberry, US Ambassador to Afghanistan:
We extend our condolences to the people of Kandahar and to the family of Mr. Karzai.

William Crosbie, Canada's Ambassador to Afghanistan:
"Canada strongly condemns the assassination of Kandahar Provincial Council Chair Ahmad Wali Karzai and extends its condolences to his family and to President Hamid Karzai. Canada will continue to work with Afghans, the majority of whom reject senseless violence, to build a better governed, more stable and secure country free of conflict."

Mirwais Yasini, MP from Nangarhar Province:
"The killing of Ahmad Wali Karzai is a big loss to the Afghan people, especially to the people of Kandahar. He was an influential man, a bridge for bringing tribes together in harmony."

Haroun Mir, Director of Afghanistan's Centre for Research and Policy Studies:
"Ahmad Wali Karzai is irreplaceable in Kandahar. His death will leave a vacuum. Despite all the criticism, he was a stabilizing factor in Kandahar. "Now Ahmad Wali Karzai is not there, others in Kandahar will be afraid. This is a real boost to the Taliban," he added.

Michael O'hanlon, A Senior Fellow in Foreign Policy and Defense at the Brookings Institution:
"Some people considered AWK (Ahmad Wali Karzai) a major problem and will be hopeful this event, however sad at a human level, may open up new opportunities.
"Others will see it as just further proof that Afghanistan is mired in a rut of killing and assassination, or worry that with the big man gone, the competition for the spoils will intensify and further confuse and fracture the process."

A Senior Western Diplomat in Kabul:
"I'm certain that the killing of AWK will have profound political consequences, but it is too early to assess this more concretely now. We need to know more about the underlying motives of the killing and which actors now will move in to fill the lacuna after AWK." (Reuters)