Pakistan's military leader, General Pervez Musharraf, has said that the Taliban's killing Abdul Haq would have no impact on attempts to establish a new political regime in Afghanistan.
The opposition commander was captured and executed in the east of the country yesterday.
Meanwhile, the Afghan capital Kabul has seen its heaviest bombardment since the military campaign began.
The Taliban earlier denied that it hanged five opposition Northern Alliance commanders who were captured in northern Afghanistan.
The Afghan Islamic Press earlier reported, quoting Taliban sources, that five commanders, along with 15 fighters were hanged.
However, Taliban Education Minister Amir Khan Muttazi has denied the story. "No such incident occurred, it is wrong and we refute it," he said.
In a separate development, the United States Defence Department said that American planes inadvertently dropped bombs on Red Cross warehouses in the Afghan capital, Kabul, and a residential area near them yesterday.
The warehouses have been damaged twice since the US-led bombing of Afghanistan began earlier this month.
The Geneva-based relief agency said that the roofs of the buildings were clearly marked with the Red Cross emblem and the attacks violated international humanitarian law.
