Six killed as gunmen attack Pakistani stock exchange, say police
Khan offered no evidence for his allegation but said there had been intelligence reports warning of attacks in Pakistan and he had informed his cabinet about the threat.
He said the attackers were heavily armed and wanted to take hostages to replicate the 2008 Mumbai attacks in which more than 160 people were killed.
Khan termed their failure to do so and the rapid response by security forces, as a "big victory".
AFP Rizwan Tabassum, AFP
The Baloch Liberation Army (BLA), an armed separatist group from the southwestern province of Balochistan, claimed responsibility for the attack in a message.
The group has been officially banned in Pakistan since 2006 and was classified by the United States as a global terrorist group last July.
Khan said Pakistan's intelligence agencies had successfully pre-empted at least four major attacks in the country, two of which targeted Islamabad - but that it was not possible to stop all such attacks.
Separatists have been fighting for years in Balochistan, complaining its mineral wealth is unfairly exploited by Pakistan's richer, more powerful provinces.
Pakistan has regularly blamed India for supporting Baloch separatists - a charge Delhi has repeatedly continuously denied.
The BLA also took responsibility for an attack on the Chinese consulate in Karachi in 2018.
Several projects linked to China's Belt and Road initiative are in Balochistan.