Russian Deputy Prime Minister Yuri Borisov on Sunday said S-400 air defence missile systems will be delivered to India in strict accordance with the schedule.

"The advance payment has been received and everything will be delivered in strict accordance with the schedule, within about 18-19 months," Borisov told state-owned broadcaster Rossiya-1.

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

China was the first foreign buyer to seal a government-to-government deal with Russia in 2014 to procure the lethal missile system.

Last month, External Affairs Minister S Jaishankar was in Moscow to meet his Russian counterpart Sergey Lavrov to discuss ways to further advance bilateral cooperation.

India had signed a USD 5.43-billion deal with Russia for the purchase of five S-400 systems during the 19th India-Russia Annual Bilateral Summit in New Delhi on October 5 last year for long-term security needs.

The purchase comes in the wake of the US stating on multiple occasions that?India acquiring the S-400 missile defence system from Russia is a "problem."

Senior Trump administration officials have previously cautioned India that the S-400 deal could attract sanctions under the Countering America's Adversaries Through Sanctions Act (CAATSA) law that restricts defence purchases from Russia, Iran and North Korea.

(With inputs from ANI)