"Today we received a message from the embassy of Pakistan saying that since this issue has arisen in media, we cannot cooperate and we apologise for that," said Mohammad Yasin Zia, deputy head of the National Directorate of Security.
Rabbani's killing in Kabul on September 20 has prompted Karzai to reconsider his strategy for talking peace with the Taliban. The NDS, Afghanistan's intelligence service, said it had handed evidence in Rabbani's killing to Pakistani officials to take action last Thursday.
It has also alleged that the killer was a Pakistani and the attack was planned in the Pakistani town of Quetta. Pakistan has questioned the evidence provided to its embassy in Kabul, and described Rabbani as a great friend of Pakistan, who was widely respected in the country.