"We believe firmly that there is a particular intelligence agency behind it," presidential spokesman Homayun Hamidzada told reporters of Monday's blast.
He would not name the agency but said it was "very obvious" whom he was referring to.
A senior government official who did not want to be identified told AFP separately: "Pakistan was behind the attack on the Indian embassy."
Hamidzada said the attack was "designed outside Afghanistan and it was exported to Afghanistan" with the help of local collaborators.
"The sophistication of this attack and the kind of materials used and the specific targeting, everything has the hallmark of a particular intelligence agency that has conducted similar terrorist acts in Afghanistan in the past," he said.
Afghanistan regularly accuses circles in Pakistan of supporting the Taliban and other insurgents.
Pakistan rejects the accusation.
A security report to the Afghan cabinet on Monday also accused a foreign intelligence agency of involvement in the suicide attack, the deadliest in Kabul which left nearly 150 wounded.