India meets the criteria for a US sanctions waiver for procuring S-400 missile defence systems from Russia and the Trump administration has "enough flexibility" on the issue, diplomatic sources said Tuesday, asserting that New Delhi cannot "wish away" its longstanding defence ties with Moscow.

The pitch for a waiver came a day before talks between External Affairs Minister S Jaishankar and his American counterpart Mike Pompeo during which the issue is likely to figure.

There has been a discussion on the issue with the US, both in private as well as in public domain, and it is of "some concern" to Washington, diplomatic sources said.

"We have a longstanding defence relationship with Russia which we cannot wish away," a source said.

India inked an agreement with Russia in October last year to procure a batch of the missile systems at a cost of Rs 40,000 crore. India went ahead to seal the deal notwithstanding the US' warnings against it.

The US is well aware of the circumstances that "compelled" India to go for a system like S-400, the sources said.

The Indian side has explained the rationale very well to the US side and they are appreciative of India's requirement, they said.

The Indian side feels that it meets the requirements for waiver in the Countering America's Adversaries Through Sanctions Act.

"We meet the CAATSA conditions for waivers from our point of view. We continue to remain engaged," the source said.

"The legislation is very clear as to what circumstances a waiver can be given by the administration. So if you look at purely from the legal point of view, our understanding and assessment is that India fulfils those requirements," the source said.

"So, the (Trump) administration has enough flexibility to give us the waiver that we look for," the source added.

It will have to be a combination of legal and political stand of the US government, keeping in mind the strategic US-India ties, the sources said.

The Indian government had said earlier that it will start receiving the missile systems from Russia from October next year and the deliveries will be completed by April 2023.

There were apprehensions about the payment mechanism for the deal in the wake of the US sanctions against Russia.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)