New Delhi says supplies of missile defence systems began this month, adding talks between leaders of Russia and India didn't figure Washington's warnings against the $5 billion purchase.
India has confirmed that Russia this month began deliveries of its long-range S-400 ground-to-air missile defence system, which has prompted threats of US sanctions.
"Supplies have begun this month and will continue to happen," Indian Foreign Secretary Harsh Vardhan Shringla said on Monday.
Shringla was speaking with the media after a meeting between Indian Prime Minister Narendra Modi and Russian President Vladimir Putin at India-Russia Annual Summit in New Delhi.
Regarding the US' Countering America's Adversaries Through Sanctions Act (CAATSA), Shringla said: "I don't think this issue came up at all in talks with the Russian delegation."
Russia has long been a key arms supplier to India, which is looking to modernise its armed forces, and the S-400 missile system is one of their most high-profile current contracts.
The deal is worth over $5 billion and was first signed in 2018, but it threatens to upend the burgeoning relationship between New Delhi and Washington.
Possible US sanctions
"Our Indian friends clearly explained that they are a sovereign country and that they will decide whose weapons to buy and who will be India's partner," Kremlin spokesman Dmitry Peskov told reporters on Monday.
Washington has long tried to deter countries from buying military equipment from Russia, threatening them with punitive measures under CAATSA.
Lloyd Austin, the US Secretary of Defence, reiterated during his March visit to India that all US allies and partners should shun Russian hardware and "avoid any kind of acquisition that would trigger sanctions."
A 10-year defence technical cooperation agreement and a one-year oil contract were among the deals signed as Putin held talks with India's Modi.
India will also produce more than 600,000 Kalashnikov assault rifles under the agreement.
Russia 'won't act' against China interests
It was only Putin's second trip abroad since the coronavirus pandemic began –– he skipped both the G20 and COP26 summits this year –– and comes after a June summit with US President Joe Biden in Geneva.
Putin's visit comes in the shadow of complex regional dynamics, with tensions mounting between India and China, traditionally an ally of Moscow, following deadly clashes in a disputed Himalayan region that left nearly two dozen Indian soldiers dead.
"Russia's influence in the region is very limited," said Tatiana Belousova of OP Jindal Global University in Haryana, "mostly because of its close ties with China and unwillingness to act in dissonance with the Chinese regional interests."