New Delhi, Sep 21 (IANS): Prime Minister Manmohan Singh Wednesday condoled the death of Afghan leader Burhanuddin Rabbani, killed in a suicide blast at his house in Kabul Tuesday, and described it as a "senseless act of terrorism".

In a letter to Afghan President Hamid Karzai, Singh said the best tribute the people of Afghanistan could pay to the departed leader was to carry on with the task he had begun: securing a peaceful and safe future for the people of Afghanistan.

Former Afghan president Rabbani headed a government peace council set up to broker peace with the Taliban.

In a statement, before leaving on a six-day visit to participate in the 66th session of the United Nations General Assembly, Singh said: "It is with great shock and sadness that I have learnt of the tragic death of professor Burhanuddin Rabbani.

"This is a senseless act of terrorism, which the government and people of India condemn," the statement said.

Recalling his two meetings with the former Afghan president, Singh said he "fondly" remembered his two meetings with him -- in Kabul in May 2011 and in New Delhi in July 2011.

He said, during their meetings, Rabbani shared with him "his vision of peace and reconciliation in Afghanistan".

"Please accept my deepest condolences on the tragic loss. I wish to assure your excellency that India stands by you and the people of Afghanistan in this hour," he said.