The head of NASA has branded India's destruction of one of its satellites — that created 400 pieces of orbital debris and led to new dangers for astronauts aboard the International Space Station (ISS) — a “terrible thing”.

Jim Bridenstine was addressing employees of the National Aeronautics and Space Administration on Monday, five days after India shot down a low-orbiting satellite in a missile test to prove it was among the world's advanced space powers.

Not all of the pieces were big enough to track, Bridenstine explained.

“What we are tracking right now, objects big enough to track — we're talking about 10 centimeters [six inches] or bigger — about 60 pieces have been tracked.”

The Indian satellite was destroyed at a relatively low altitude of 180 miles [300 kilometers], well below the ISS and most satellites in orbit. But 24 of the pieces “are going above the apogee of the International Space Station”, said Bridenstine.

“That is a terrible, terrible thing to create an event that sends debris at an apogee that goes above the International Space Station,” he continued, adding: “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 US military tracks objects in space to predict the collision risk for the ISS and for satellites. They are currently tracking 23,000 objects larger than 10 centimeters. That includes about 10,000 pieces of space debris, of which nearly 3,000 were created by a single event: a Chinese anti-satellite test in 2007 at 530 miles from the surface.

As a result of the Indian test, the risk of collision with the ISS has increased by 44 percent over 10 days, Bridenstine said. The risk, however, will dissipate over time as much of the debris will burn up as it enters the atmosphere.

Indian Prime Minister Narendra Modi last week announced that the country had destroyed a low-orbiting satellite in a missile test, becoming the fourth country in the world to have carried out the feat.

"This is a proud moment for India," the prime minister had said in his first televised national address since late 2016.

"India has registered its name in the list of space superpowers. Until now, only three countries had achieved this feat," he said, just weeks before the country goes to the polls.

Pakistan, in a statement through the Foreign Office, had stated it "has been a strong proponent of the prevention of arms race in outer space".

The statement asserted that space is a "common heritage of mankind" and as such responsibility falls on every nation "to avoid actions which can lead to the militarisation of this arena".

Pakistan expresses 'deep concern'

Pakistan expressed "deep concern" on Tuesday over threats emanating from space debris generated by the recently conducted Anti-Satellite weapon (ASAT) test by India, a statement issued by the Foreign Office said.

"The reports that some of the space debris created by this test has been pushed above the apogee of the International Space Station (ISS) increasing the risk of collision are deeply worrying," said the statement.

The Foreign Office in its statement said that the ASAT test should be "a matter of grave concern" for the entire international community not only because of the debris it generated but also because of the "ramifications for long term sustainability of peaceful space activities".

"It would also be amiss to ignore the military dimension of such actions and its implications on the global and regional peace, stability and security," said the Foreign Office statement.

The Foreign Office reiterated Pakistan's stance as a "strong proponent of non-militarisation of outer space".

"We will continue to work with like-minded countries to address gaps in the international legal regime governing the exploration and use of outer space with a view to ensuring that no one threatens peaceful activities and applications of space technologies for socio-economic development," the Foreign Office said in its statement.

The statement further cautioned against other states following suit "by demonstrating such capabilities" in the absence of strong legal instruments.