UNITED NEWS INTERNATIONAL (UNI) — India is moving forward with plans to purchase Russian air defense missile systems despite the threat of U.S. sanctions.

India’s defense ministry confirmed on June 5 that it will move ahead with the procurement of five regiments of Russian-made S-400 Triumf advanced Air Defense Systems in a deal worth roughly $5.5 billion.

India’s interest in the S-400s — dubbed “F-35 killers” by Moscow — reportedly intensified after reports surfaced that Russia had already begun deliveries of the system to regional rival China.

The S-400 deal could potentially make India liable under the Countering America’s Adversaries Through Sanctions Act signed by President Trump last August.

The act, which targeted Russia for its interference in the 2016 presidential election and annexation of Crimea, requires sanctions against any country that strikes “highly-significant” agreements with Russia’s defense industry.