India's #ASATMissile test 'terrible thing'; created 400 debris pieces: NASA

Bridenstine said that not all debris pieces were big enough to track.

"...Objects big enough to track--we're talking about 10 centimeters (six inches) or bigger--about 60 pieces have been tracked," he said.

India destroyed its satellite at a 300km satellite, which was well below the ISS and most other satellites.

He, however, said 24 pieces "are going above" the apogee of the ISS.

"That is a terrible, terrible thing to create an event that sends debris at an apogee that goes above the International Space Station," Bridenstine said on India's ASAT missile test.

"That kind of activity is not compatible with the future of human spaceflight. It's unacceptable and NASA needs to be very clear about what its impact to us is," the NASA Administrator added.

Objects in space are tracked by the US military to predict collision risk for ISS and satellites.

Currently, 23,000 objects bigger than 10cm are being tracked, including 10,000 space debris pieces. Nearly 3,000 debris pieces were created by China's 2007 anti-satellite test at about an altitude of 853km.

Bridenstine said India's test has increased collision risk for ISS by 44% over 10 days.