Pakistan will soon test for the first time a new nuclear-capable missile that could reach all of India's cities.
Pakistan said the missile, the Shaheen II, has a range of over 1,200 miles, although one Pakistani newspaper has reported its range could be as high as 1,900 miles.
The new missile exceeds the 930-mile reach of the Ghauri, previously Pakistan's longest-range missile which some say was developed with North Korean help.
Pakistan says its weapons programme is a response to that of nuclear-armed rival India, with which it has fought three wars since independence from Britain in 1947.
The planned test of the Shaheen II comes amid intense scrutiny of Pakistan's nuclear programme after revelations its scientists sold nuclear secrets to Iran, North Korea and Libya.
"Our strategic force goals are guided by the concept of minimum credible deterrence and that's why we have to test these missiles from time to time," Mr Khan said.
The test comes amid warming ties between Pakistan and India, and Mr Khan said the two rivals had a policy of informing each other ahead of a missile test.
Mr Khan said the aim of the test would be to ensure its missile "reach" was sufficient to deter aggression and "prevent military coercion".