If Southeast Asian nations such as Vietnam acquire the missile, that could raise concerns in China.

India and Russia have jointly developed the world's fastest supersonic cruise missile and plan on exporting the technology to allies.

BrahMos Aerospace, a joint venture between India and Russia, has developed what it calls the world's fastest supersonic cruise missile. The namesake rocket may now be exported globally — a potentially concerning development for the world's second-largest economy. A BrahMos spokesperson told CNBC at this year's Singapore Airshow that discussions were underway "with a number of countries," adding that the company would only sell to "responsible" nations friendly with both New Delhi and Moscow.

The BrahMos weapon system in full display during a rehearsal for India's Republic Day Parade on January 23, 2018 in New Delhi. Mohd Zakir / Hindustan Times / Getty Images

Many Southeast Asian countries, including Malaysia, Indonesia and Vietnam, are reportedly interested in purchasing the state-of-the-art BrahMos missile, which has a flight range of nearly 300 kilometers. Hanoi is currently locked in a territorial dispute with Beijing in the South China Sea, so a purchase of the missiles could be seen as an escalation from the Chinese perspective. If the transaction materializes, "that would demonstrate an Indian willingness to arm a state right on China's doorstep for the first time," said Shashank Joshi, senior research fellow at the Royal United Services Institute for Defence and Security Studies. Indian Prime Minister Narendra Modi's administration has denied reports that it was selling to Hanoi, but officials in the communist state have hinted that a deal was in place. Dubbed "the carrier killer," the BrahMos can be launched from land, sea and air. Low maintenance requirements make it the most cost-effective model among existing cruise missiles systems, according to the firm. The rocket is able to precisely target enemy assets such as bunkers and radar systems, similar to what U.S. Tomahawk missiles did to Islamic State infrastructure.