"We are still characterising this event. We expect the debris will grow over time," Shaw said.
The Deputy Commander explained that the debris will become a threat that will eventually have to be dealt with.
On Monday, the Space Command said Russia tested a direct-ascent anti-satellite (DA-ASAT) missile that struck a Soviet-era Cosmos 1408 satellite, created a field of debris in low-Earth orbit.
NASA Administrator Bill Nelson said on Tuesday that he held a telephone conversation with Roscosmos CEO Dmitry Rogozin to express concern over the danger astronauts and cosmonauts encounter on the International Space Station from the debris.