Afghanistan's intelligence agency says Pakistan is refusing to cooperate with a probe into the killing of top Afghan peace envoy and former President Burhanuddin Rabbani.

The deputy head of Afghanistan's National Directorate of Security, Mohammad Yasin Zia, told reporters on Tuesday that the agency received a message from the Pakistani embassy saying Pakistan could not assist in the investigation because details had been leaked to the media.

But Pakistan's ambassador to Kabul, Mohammad Sadiq, told Reuters news agency there had been a misunderstanding and that the embassy had sent a letter reaffirming Pakistani cooperation.

Former Afghan President Burhanuddin Rabbani, the head of the High Peace Council, was killed in a suicide bombing at his Kabul home on September 20.

Afghan officials say the attack was planned in Pakistan and carried out by a Pakistani citizen. The Afghan intelligence agency says it has handed over evidence to Pakistan.

Pakistan has rejected allegations of involvement in Mr. Rabbani's killing.

On Monday, Afghan President Hamid Karzai accused Pakistan of playing a “double game” on terrorism and said Pakistan was not supporting efforts to bring peace and security to Afghanistan.