Karzai said he had heard the CD, passed to him by a High Peace Council representative, before Rabbani's assassination and initially thought it carried the peace message.

The Afghan president then headed to the United States but cut short the visit after Rabbani was killed at his Kabul home on Tuesday. Officials say the killer had waited in the Afghan capital for up to four days to see him.

In an emotional press conference in the presidential palace gardens, Karzai said: "We saw that that message was not a message of peace, it was rather a deception... and the peace emissary was a murderer."

Rabbani, chairman of Karzai's High Peace Council, was killed by a bomber wearing explosives in his turban.

The Taliban have yet to claim responsibility for the attack but officials have blamed them for carrying it out.