NEW DELHI — Prime Minister Narendra Modi of India announced on Wednesday that India had test-fired an interceptor rocket that shot down a satellite, escalating the country’s rivalry with China and Pakistan, and demonstrating a strategic strength that few countries can claim.
If confirmed, a successful anti-satellite test could destabilize the balance of power between India and Pakistan, both nuclear powers that for years have eyed each other warily, with hostilities briefly breaking out last month.
This technological leap puts India in the exclusive club of nations, along with the United States, Russia and China, that have proved their ability to destroy targets in space. This could be a crucial advantage in war, allowing a country essentially to blind another by taking out the enemy’s space-based communication and surveillance satellites.
It is no easy feat. In this case, scientists estimate that the satellite that India claims to have blasted apart was moving around the Earth at 17,000 miles per hour.
Mr. Modi made the announcement to a rapt nation just weeks before the country heads into a hotly contested election.
“India stands tall as a space power!” Mr. Modi tweeted after his announcement. He added that the entire effort was “indigenous,” accomplished entirely by Indians.
When China first successfully tested such an anti-satellite missile in 2007, it set off global concern over the growing weaponization of space.
Many analysts now worry that the regional rivalry between India and China, the two most populated countries in the world, has moved into space.
India’s test was a “demonstration against China,’’ said Kazuto Suzuki, an international relations professor at Hokkaido University in Japan and an expert on space security.
“The proliferation of this technology and capability would make the space order very unstable,’’ he said.
No other country has yet confirmed that India actually shot down a satellite. The United States, Europe, Japan and a few others have the ability to track space debris as small as a softball, but experts said it was unlikely that India would present this as a successful test if it hadn’t actually happened.
Mr. Modi broke the news in a rare televised address to the nation, and many Indians immediately suspected that his primary objective was more political than technological.
In a little more than two weeks, India will begin holding an election — billed as the biggest in human history, with nearly 900 million registered voters — and Mr. Modi is up for re-election. Leaders in his political party have recently been heckled in public and attendance has been poor at rallies for some of his party’s candidates.
Though Mr. Modi enjoyed a burst of popular support after India conducted airstrikes last month in Balakot, Pakistan, in retaliation for a deadly suicide bombing by militants against Indian forces, that news has mostly subsided.
The announcement “shows a poll-eve desperation we hadn’t yet detected/suspected,” tweeted Shekhar Gupta, one of India’s best known political commentators. “It’s just a frantic new national security headline as Balakot has faded in a month.”
On Wednesday morning, Mr. Modi posted a message on Twitter, which he uses frequently, telling Indians to tune in because he was about to make a major announcement.
Many people believed the speech would be related to Pakistan; tensions had risen very fast and very high last month after Indian warplanes dropped several bombs on the site in Balakot where Indian authorities said anti-India militants were hiding. It is not clear what if anything the Indian Air Force hit.
But the next day Pakistan shot down an Indian fighter jet and captured the pilot, pushing the two nations dangerously close to a major conflict. Both wield nuclear arsenals. Pakistan quickly defused the situation by releasing the pilot.
The whole episode brought Mr. Modi a crest of support. The old, thorny issues that had been dogging him — such as rising unemployment, poor drinking water and widespread distress among farmers — disappeared for a moment.
Flags came out across the country. Even Indians who didn’t necessarily agree with the Hindu nationalist flavor of Mr. Modi’s party still cheered him on.
But in the past few days, the electoral mood seems to have changed once again. Complaints about jobs, health care and farm subsides have been rising.
The Indian National Congress, the leading opposition party, scored some points after its leader, Rahul Gandhi, the scion of a longstanding political dynasty, promised that Congress would give the equivalent of $1,000 to India’s poorest families.
Around noon, when Mr. Modi was set to address the nation, the streets of New Delhi, the capital, grew uncharacteristically quiet. Many people ducked inside shops to watch TV.
Saurav Jha, the editor in chief of “Delhi Defence Review,” an online defense related magazine, said that successfully shooting down a satellite was a major achievement.
“It’s as significant as India’s first nuclear blast,” he said.
India has been steadily advancing its space program since its first satellite launch in 1975. It joined a manned space mission with Russia in 1984 and launched a Mars orbiter in 2013. This December, India sent its heaviest communication satellite so far, weighing nearly 5,000 pounds, into space.
A big motivation clearly is China. As China has stepped up its satellite launches and space probes, India has been trying to catch up.
The test, Mr. Jha said, was “very much the part of the India-China rivalry.”
Another factor may have been archrival Pakistan. Last year, China helped Pakistan launch a remote sensing satellite. India’s test showed it could blast apart the Pakistani eye in the sky, turning it into space garbage.
This could make the bitter regional contest between India and Pakistan even more dangerous. Before this test, the two militaries were widely viewed as comparable. Each side has been reluctant to start a major conflict, fearing that the other could stage a devastating counter attack.
But some analysts said that if India has now gained superiority in anti-satellite warfare, it might be able to stage a pre-emptive attack on Pakistan’s satellites, or even Pakistan itself. That could unsettle the longstanding doctrine of mutually assured destruction that both countries have followed, and put Pakistan even more on edge.
“The militarization of space is underway, whether anybody likes it or not,” Mr. Jha added. Part of the reason, he said, was that satellite technology had become “the backbone of global communication.”
Mr. Jha and other analysts said that China, the United States and Russia have been discussing a space nonproliferation treaty, and that with this test India’s position must now be considered as well.
The Indian government did not reveal what kind of satellite it shot down; the Ministry of External Affairs described it as “one of India’s existing satellites operating in a lower orbit.”
Mr. Modi has revived the notion that he is India’s “chowkidar,” or watchman, and looking tough in space seemed to fit nicely with that image.
“Today’s success, in the coming days, will be seen as India’s forward march toward a secure nation, a rich nation and a peaceful nation,” he said.
The test was conducted within three minutes on Wednesday morning, he said, and the satellite was flying about 186 miles above Earth. It was low enough, Indian officials said, that its debris will decay and fall back to Earth.
In 2012, Indian scientists announced they had the capability to shoot down a satellite but that it would take 24 months to prepare for such a test.
Some analysts wondered if Mr. Modi, who is known as a cunning political strategist, planned as early as two years ago to conduct this test right before this year’s election, to give him a late-in-the-game boost.
“The timing indicates that there is politics around this,’’ said N. K. Singh a political analyst. “The issues of food, clothing, housing and employment are emerging on the surface in bigger way.”
He added: ”Nobody can say for sure but the perception of politicization is there.”