Washington: Terming the assassination of former Afghan president Burhanuddin Rabbani as a "senseless act of violence", US President Barack Obama has said the attack will not deter America in helping Afghanistan on its path to safety and prosperity.

Obama met his Afghan counterpart Hamid Karzai on the sidelines of the UN General Assembly and offered his condolences to the people of Afghanistan, shortly after the attack.

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The US President said the killing was a "senseless act of violence" that would not crush the Afghan drive for freedom.

"I think we both believe that despite this incident, we will not be deterred from creating a path whereby Afghans can live in freedom and safety and security and prosperity, and that it is going to be important to continue the efforts to bring all elements of Afghan society together to end what has been a senseless cycle of violence," Obama said.

"He was a man who cared deeply about Afghanistan and had been a valued advisor to President Karzai, and was a enormous contribution to rebuilding the country. So it is a tragic loss. We want to extend our heartfelt condolences to you and to his family, and the people of Afghanistan," he said.

Karzai said the mission undertaken by Rabbani was vital, for the Afghan people and for the peace and security of his country.

"We will miss him very, very much. I don't think, Mr President, that we can fill his place easily. He was one of the few people in Afghanistan with the distinction that we cannot easily find in societies. A terrible loss, but as you rightly say, this will not deter us from continuing on the path that we have, and we'll definitely succeed," the Afghan President said.
Secretary of State Hillary Clinton, in a statement, condemned in the strongest terms the assassination of Rabbani.

"We will support the Afghan government as they pursue the ones responsible for this cowardly attack and bring them to justice. And we will continue to increase pressure on al-Qaeda and the Taliban," she said.
"We have always known that there are those who will do all they can to undermine the cause of peace and reconciliation. We will see more violence before this is over."
Admiral Mike Mullen, Chairman of the Joint Chiefs of Staff, said it was too early to say if the Haqqani network was behind the attack.
"I think we do take it very seriously, first of all. Secondly, I don't have the details of this, other than what's been reported, so I couldn't tell you who's behind it," he told reporters at a Pentagon news conference.

"I think there are those that would immediately finger Haqqani specifically. I just don't -- I can't validate that one way or another," Mullen said.