India's Prime Minister Narendra Modi said the country had joined the space “super league” on Wednesday after it successfully tested an anti-satellite system.
Mr Modi said the system shot down a low-orbit satellite, making it the fourth nation after the US, Russia and China to have used an anti-satellite missile.
Pakistan criticised the test, saying that space was “the common heritage of mankind” and should not be militarised.
"In the journey of every nation, there are moments that bring utmost pride and have a historic impact on generations to come. One such moment is today," Mr Modi wrote on Twitter.
Announcing the mission on television, the prime minister said India had joined the space "super league".
Mr Modi, who faces elections next month, said the mission was special because India had developed the technology.
Anti-satellite systems have been tested but have never been used in conventional warfare.
But the growth in anti-space weaponry, and initiatives such as US President Donald Trump’s planned “Space Force” military branch, have raised fears of weapons in space and a race between rivals for supremacy.
"Space is being turned into a battle front, making counter-space capabilities critical,” said Brahma Chellaney, a security expert at New Delhi's Centre of Policy Research.
"In this light, India's successful 'kill' with an Asat weapon is significant."
China's Foreign Ministry said it hoped all countries "can earnestly protect lasting peace and tranquillity in space".
The US and Russia both declined to make any immediate comment.
Anti-satellite weapons allow for attacks on enemy satellites, blinding them or disrupting communications, and provide a technology base for intercepting ballistic missiles.
"Our scientists, shot down a live satellite 300 kilometres away in space, in low-earth orbit," Mr Modi said.
"India stands tall as a space power. It will make India stronger, even more secure and will further peace and harmony."
The announcement met praise in India, with many calling it the birth of a "super science power".
"Massive Space Leap for India. Kudos to DRDO [Defence Research and Development Organisation] scientists for this huge technological advancement," said Suresh Prabhu, India's Minister for Commerce and Industry and Civil Aviation.
India has had a space programme for years, making Earth-imaging satellites and launch capabilities as a cheaper alternative to western programmes.
It successfully sent a low-cost probe to Mars in 2014 and plans its first manned space mission by 2022.
The latest test, conducted from an island off India's east coast, was aimed at protecting Indian assets in space against foreign attacks, the government said.
"The capability achieved through the anti-satellite missile test provides credible deterrence against threats to our growing space-based assets from long-range missiles, and proliferation in the types and numbers of missiles," the Foreign Ministry said.
The test lasted three minutes and was done in the lower atmosphere to ensure there was no debris in space, and that whatever was left would "decay and fall back on to the earth within weeks", the ministry said.
China destroyed a satellite in 2007, creating the largest orbital debris cloud in history, with more than 3,000 objects, the Secure World Foundation said.
But some claimed Mr Modi was misusing technological progress for political gains ahead of elections next month.
Pankaj Pachauri, a prominent TV presenter, said it was "a misuse of India’s great defence capabilities for electoral-political gains".
Mr Modi, who leads a Hindu nationalist-led government, has taken a strong position on national security, launching air strikes last month on a suspected militant camp in Pakistan that led to retaliatory raids in a dramatic increase of tension between the nuclear-armed rivals.
Hours after the announcement, Pakistan criticised the test.
"Space is the common heritage of mankind and every nation has the responsibility to avoid action that can lead to the militarisation of this arena," Pakistan's Foreign Ministry said.
"We hope countries that have in the past strongly condemned demonstrations of similar capabilities by others will be prepared to work towards developing international instruments to prevent military threats relating to outer space."
Mr Modi faces criticism for failing to deliver on high economic growth and create jobs, but a hawkish position on security could help him at the ballot box.