India plans to use units of a Russian-purchased S-400 air defense system — which utilizes a mobile, surface-to-air missile system — to defend itself against potential threats posed by neighboring China as soon as June, the Press Trust of India (PTI) reported on Wednesday.

“In December India received its initial delivery of the Russian S-400 air defense system, and it intends to operate the system to defend against Pakistani and Chinese threats by June 2022,” U.S. Lt. Gen. Scott Berrier told members of the U.S. Senate Armed Services Committee during a recent U.S. Congressional hearing, as quoted by PTI. Berrier serves as the Director of the United States Defense Intelligence Agency, the nation’s highest-ranking military intelligence officer.

Russia’s S-400 air defense system is considered the nation’s “most advanced long-range surface-to-air missile defence system,” PTI noted in January while reporting on the U.S. government’s open disapproval of New Delhi’s decision to acquire the military equipment from Moscow.

“The administration [of U.S. President Joe Biden] has made clear that it is discouraging India from proceeding with the acquisitions of Russian equipment, and there are important geostrategic considerations, particularly with (unintelligible) relationship to China,” James C. O’Brien, the head of the U.S. Office of Sanctions Coordination, said at a confirmation hearing for the position on January 12.

India inked a $5 billion deal with Russia in October 2018 to purchase five units of the S-400 air defense missile systems in subsequent months. The two parties finalized the agreement despite repeated public warnings by Washington that the pursuit of such a contract could invite U.S. sanctions on New Delhi.

“We certainly urge all our allies, our partners to move away from Russian equipment … and really avoid any kind of acquisitions that would trigger sanctions on our behalf,” U.S. Defense Secretary Lloyd Austin told reporters in New Delhi following an in-person meeting with his Indian counterpart on March 20, 2021.

At the time, India had yet to take possession of any of the five S-400 air defense system shipments it ordered from Russia in October 2018. New Delhi began receiving its initial batches of the Russian military equipment in December 2021.

India’s military stationed its first set of S-400s “at an Indian Air Force base in Punjab [a northwestern Indian state bordering Pakistan], duly tasked to tackle air-borne threats from Pakistan and China,” India’s the Tribune newspaper observed on April 16.

“By [the] end of this month [April], the delivery of the critical system will be completed and thereafter it will be deployed, expectedly by June. The location of the base where the [final shipments of the] systems will be deployed is not known but is estimated to be in the north-east [of India],” the Tribune revealed.

Much of India’s northeastern border is shared with China. The two Asian giants have been engaged in an unofficial Himalayan border standoff since June 2020, when Chinese troops launched a surprise attack on an Indian border regiment in the northern Indian state of Ladakh’s Galwan Valley. The skirmish killed 20 Indian troops and at least 38 Chinese People’s Liberation Army (PLA) soldiers.