NEW DELHI (PTI): As the threat of US sanctions lingers after the signing of the S-400 air missile defence system deal with Russia, experts feel there is a certain understanding in Washington on New Delhi's position which may allow India to avoid American action.

Strategic affairs expert Commodore (retd) C Uday Bhaskar said the US$ 5 billion deal, signed between India and Russia on Friday during the two-day visit of Russian President Vladimir Putin, is going to test the resilience of the India-US relationship.

The deal could attract sanctions under CAATSA (Countering America's Adversaries Through Sanctions Act), a legislation that is aimed to counter Russia, Iran and North Korea through punitive measures by imposing restrictions on deals in defence and strategic areas.

“During the 2 plus 2 dialogue, the Modi government had conveyed to the US that for India, the military relationship with Moscow is very deep and goes back to the 1960s. So I feel there is a certain understanding in the US on the Indian position,” he said.

He added that as a major arms importer, India is vulnerable, but it cannot allow any country to issue a diktat about its security needs.

Former diplomat Anil Wadhwa, who was a Joint Secretary in the Ministry of External Affairs looking after Russian affairs, said the deal was under negotiations way before CAATSA came into force.

He said the issue has to be dealt on case-by-case basis and the US should give a waiver to the deal.

The US administration has to put up a strong case before the Congress. Anyways, there is a strong support for India in the Congress from both the parties, he asserted.

India and Russia, he said, must come up with a mechanism to circumvent the sanctions if there is any.

Rajeshwari Rajgopalan, Senior Fellow and Head of the Nuclear and Space Initiative of the Observer Research Foundation, said one of the reasons behind India going ahead with the deal was the technological superiority of the S-400 missile defence system.

The US is well aware of India's requirement for the defence missile system and it could escape sanctions, she said.

Rajgopalan added that it is unlikely that US may give any further concessions to India, especially on its oil imports from Iran.