NEW DELHI, July 13 (Xinhua) -- Indian Defense Minister Nirmala Sitharaman on Friday said the S-400 Triumf air defence missile deal with Russia will go ahead despite U.S. sanctions on military transactions with Moscow.

Talking to reporters at her office, Sitharaman said that negotiations are in final stages with Russia for the S-400 missile.

"Our defence relation with Russia has endured several decades and we have conveyed about it to a U.S. Congressional delegation which visited India recently," she was quoted as saying.

She said that the U.S. Adversaries Through Sanctions Act (CAATSA) is an American law and not a UN law, thus it's not applicable to India.

The minister said it may take two-and-a-half to four years to implement the S-400 missile deal after it is signed.

S-400 is known as Russia's most advanced long-range surface-to-air missile defence system.

India intends to procure long-range missile systems to tighten its air defence.

Reports said in 2016, India and Russia had signed an agreement on the Triumf interceptor-based missile system, which can destroy incoming hostile aircraft, missiles and even drones at ranges of up to 400 km.