Afghan President Hamid Karzai is pushing ahead with a reintegration and reconciliation program with members of the Taliban who renounce al-Qaida and embrace the rule of law.
Former Afghan President Burhanuddin Rabbani was tasked with steering that effort as the head of a 70-member reconciliation committee.
Rabbani was assassinated Tuesday in a bomb attack at his Kabul home. The incident came just days after an attack by suicide bombers and gunmen on the U.S. Embassy and NATO headquarters in Kabul, which U.S. officials said they suspect was the work of the Haqqani network.
Washington maintained the eruption of violence wouldn't undermine reconciliation efforts under way in Afghanistan.
U.S. Secretary of State Hillary Clinton, in a statement, said more violence can be expected in Afghanistan.
"But the Afghan people will not be deterred from pursuing a more peaceful, democratic future for their country and we will continue to stand with them and support their efforts," she said.
Former Foreign Minister and one-time presidential candidate Abdullah Abdullah was quoted by The New York Times as saying the Rabbani assassination should serve as a lesson that certain factions in Afghanistan aren't willing to make peace.
"We are up against people who don't believe in any humanity," he said, adding it was time for Karzai "to wake up."