New Delhi is expected to purchase two dozen unarmed drones from the United States to monitor growing Chinese activity in the Indian Ocean. President Donald Trump's administration authorized the sale in June, with the price tag estimated at $3 billion, according to defense researcher Jane's by IHS Markit. The U.S. approval was the first such clearance to a friendly, non-NATO nation, but the transaction has yet to be finalized and was a key topic of discussion during General James Mattis' visit to India this week. Manufactured by American defense contractor General Atomics, the unmanned devices— called Guardians — are "the world's most advanced maritime reconnaissance drones and can help India track the movement of Chinese warships with its multi-mode maritime radar," said Harsh Pant, head of the strategic studies program at the Observer Research Foundation, a New Delhi-based think tank.

General Atomics' Guardian drone, which is the maritime version of the company's Predator B or MQ-9 Reaper unmanned aerial vehicle. General Atomics

Privately held General Atomics makes the drone in question as a maritime variant of its Reaper unmanned vehicle.

China moves into Indian Ocean

The world's second-largest economy has ratcheted up maritime patrols around the Indian Ocean, which is home to seaborne routes crucial to global trade as well as a major U.S. military base. The mainland has also built up a presence in other countries around the region. July saw Beijing establish its first overseas naval base in Djibouti, located on the ocean's northwestern side. That same month, state-owned China Merchant Port Holdings acquired Sri Lanka's Hambantota Port, which juts out into the strategic waterway, in a move expected to facilitate Chinese naval deployments. It's a similiar story in Bangaldesh, where state-owned enterprise China Harbour Engineering Company bought a majority stake in Payra Port, located at the southern-most tip of the country. The mainland is also looking to take an 85 percent stake in Myanmar's deep sea port of Kyauk Pyu on the Bay of Bengal, according to reports. Occuring right in India's backyard, these projects — part of China's massive "Belt and Road" infrastructure program — are a worrying development for New Delhi, which has long held sway as the region's major power and comes just weeks following the end of a Sino-Indian border dispute in the Himalayas.