Malik said the plot was uncovered after police seized a large quantity of weapons during a raid on a home in the Chatta Bakhtawar suburb of the Pakistani capital over the weekend.
The terrorists wanted to target "certain specific places in the Red Zone", a heavily guarded area in the heart of Islamabad, and the "headquarters of an elite agency", he told reporters.
The Red Zone is home to the diplomatic enclave, the presidency, Prime Minister's House, parliament and the headquarters of the Inter-Services Intelligence (ISI) agency.
Malik said the arrested terrorists had carried out rehearsals for the planned attack, during which they planned to fire rockets at certain targets.
"As a result of strict security measures in the capital, some major terrorist plots have been foiled," he claimed.
Police had arrested two terror suspects on Saturday after finding 16 rockets, 12 grenades, four suicide vests and 90 doses of drugs allegedly used to brainwash potential bombers during the raid in Chatta Bakhtawar.
In a separate development, police in Islamabad arrested four terror suspects and seized two vehicles with caches of weapons, including Kalashnikovs, pistols and ammunition, a police spokesman said.
The seized weapons included eight machine guns, seventeen 30 bore pistols, two machine pistols and 16,420 bullets.
The weapons were hidden in secret compartments in the cars.
