I India’s Agni-V missile, with a range of 3,100 miles, lifts off from the launch pad at Wheeler Island off India's east coast on Thursday. (Indian Ministry of Defense handout/AP)

India successfully test-launched a long-range missile on Thursday that would give it the capability for the first time of sending a nuclear warhead as far as China’s capital, Beijing, officials said.

Officials and defense experts said the Agni-V missile marks a significant improvement in India’s nuclear-deterrent capability and was clearly aimed at bolstering its defense against neighboring China.

It also puts India on the cusp of a small group of nations with intercontinental nuclear weapons capabilities and burnishes its credentials as a global heavyweight.

“Today’s successful Agni-V test launch represents another milestone in our quest to add to the credibility of our security and preparedness,” Prime Minister Manmohan Singh said in a statement. Defense Minister A.K. Anthony called it an “immaculate success.”

Vijay Saraswat, head of India’s Defense Research and Development Organization, said the missile was launched just after 8 a.m. from Wheeler Island off eastern India.

It rose to an altitude of more than 370 miles, and its payload was deployed as planned, he told Times Now news channel.

“India has emerged from this launch as a major missile power,” he said.

Experts said the deployment of the missile, which is capable of carrying a 1.5 metric ton warhead at least 3,100 miles, could take several more years.

India has a “no-first-use” policy that commits it to use nuclear weapons only if attacked, and defense experts said the Agni-V would help make that threat of massive retaliation more credible. The fact that the rocket uses solid fuel and can be deployed by road also bolsters its credibility as a “second-strike” weapon in the event of a nuclear attack.

“We are located in one of the most complex and adversarial WMD environments in the world, by virtue of our geography,” said retired Commodore C. Uday Bhaskar of the National Maritime Foundation, referring to weapons of mass destruction. “This makes India’s deterrent capability more robust and more credible, and our ‘no-first-use’ commitment is also made more credible.”

India fought a brief border war with China in 1962, and relations have remained mutually wary since then. Although trade is growing, the two countries contest vast swaths of territory along their Himalayan border. India also has fought three wars with its western neighbor and arch-rival Pakistan, which also possesses nuclear weapons.

India has become the world’s largest arms buyer as it embarks on a major modernization of its armed forces.

New missile could bolster India’s arsenal (The Washington Post/Federation of American Scientists)

The new Agni, which is the Sanskrit word for fire, is seen as part of this military buildup. Although China’s nuclear-missile capability is far greater than India’s, experts said the new missile would help redress the imbalance.

“If you are in a hostile environment, power respects power,” Bhaskar said.

But China reacted frostily, with the Global Times newspaper warning that India was being swept up by “missile delusion” and recalling that it has not signed the nuclear Non-Proliferation Treaty.

“The West chooses to overlook India’s disregard of nuclear and missile control treaties,” the Communist Party’s mouthpiece said in an editorial published before the launch.

“India should not overestimate its strength,” it wrote. “Even if it has missiles that could reach most parts of China, that does not mean it will gain anything from being arrogant during disputes with China. India should be clear that China’s nuclear power is stronger and more reliable.”

The test comes just days after a failed long-range rocket launch by North Korea, although India is unlikely to face the kind of international condemnation that was directed at Pyongyang. North Korean officials called their launch a bid to send an observation satellite into space, but the United States and other countries said it was a covert test of long-range nuclear missile technology.

In 1998, the United States and other nations imposed sanctions on India after it conducted a series of nuclear tests, but today India enjoys a de facto legitimacy for its arsenal, boosted by a landmark 2008 civil nuclear cooperation deal with the United States.

On Wednesday, NATO said it did not consider India a threat. The U.S. State Department said India has a “solid” nonproliferation record, while urging all nuclear states to show restraint.

“If this had happened 15 years ago, it would have been condemned by the U.S.,” said Shashank Joshi of the Royal United Services Institute in London. “Let’s not forget the degree to which the acceptance of this is a statement about U.S.-India relations.”

Some experts characterized the Agni-V as an intercontinental ballistic missile, which would make India one of the few countries to have that capability. But Ravi Gupta, a spokesman for India’s Defense Research and Development Organization, said its range falls short of that category.

“It is India’s dream missile — I call it a game changer,” Saraswat told Times Now television before the launch.

“It is going to completely change the scenario with respect to our strategic defense.”