Top Pentagon officials have shown an understanding of India abstaining at the UN on resolutions against the Russian aggression against Ukraine but had a hard time pacifying many US lawmakers during a Congressional hearing on the Indo-Pacific on New Delhi's repeated abstention at the world body in New York.

India, a non-permanent member of the powerful United Nations Security Council for a two-year term ending December this year, has repeatedly abstained on resolutions against Russia's invasion of Ukraine.

Several US lawmakers, including Indian-American Ro Khanna, questioned the Pentagon leadership as to why India did not vote along with the US and its allies at the UN during the Congressional hearing on the Indo-Pacific on Wednesday.

"From the US perspective, I think India is an absolutely essential partner as we think about our strategy in the Indo-Pacific, and both in terms of how we're building coalition partners as well as dealing with potential adversaries. "We recognise that India has a complicated history and relationship with Russia," Ely Ratner, Assistant Secretary of Defence for Indo-Pacific Security Affairs, told members of the House Armed Services Committee.

Responding to a question from Congressman Bill Keating, Ratner said that the majority of weapons that India buys are from Russia.

"The good news is that they are in a multi-year process of diversifying their arms purchases away from Russia. That's going to take some time, but they are clearly committed to doing that, including increasing the indigenous -- indigenisation of their own defence industry.

"That's something we should support. So, I think in terms of their relationship with Russia, the trend lines are moving in the right direction," he said.

Not convinced, Khanna said.

"I'm perplexed why -- and I say this as an Indian-American, why India has abstained three times on the Security Council and is unwilling to condemn (Russian President Vladimir) Putin's unprovoked aggression into Ukraine. Do you have a view on this? And has this been raised at the highest levels with the Indian government?" Khanna asked.

He asserted that it was the US which supported India in its war against China in 1962 and again when it was engaged in a border conflict with China in 2020.

"Did Russia do anything to protect India when China was violating the Line of Actual Control, to your knowledge?" Khanna asked.

"Not to my knowledge," Ratner said.

"I know we've been engaging with Indian leadership about this issue. And as I mentioned earlier in response to a question, we're aware that India has a long history and complicated economic and security partnership with the Russians. They received a majority of their weapons from Russia historically.

"And that's something they've been working hard to wean themselves from. But defer to them to speak on their own exact decision making on this," Ratner said.

Khanna was not convinced.

"I'll just conclude by saying that I think it's obvious that the US would stand against Chinese aggression on the Line of Actual Control far more than Russia or Putin would, and that we really need to press India to not be as dependent on Russian defence and to be willing to condemn Putin's aggression in Ukraine, just like we would condemn Chinese aggression beyond the Line of Actual Control," he said.

Congressman Joe Wilson, another friend of India in Congress, said that he is shocked that "such a great country (India) has abstained on the issues of the mass murder" in Ukraine.

"I'm concerned a lot of this is because of foreign military sales and the different technicalities and whatever. What's being done to address issues to make sure that... previously brought up by Democrats and Republicans of their fondness for India that were not their main support of the military, which is in the interest of the people of India and the people of the Indo-Pacific," Wilson said.

Ratner said: "We understand and recognise that they have a long-complicated history and security partnership with the Russians, but that they've been systematically diversifying away from that, and we've been engaging with them on that question, looking for them to purchase more US systems, more European systems and develop their own indigenous capabilities as well, and I think the trend lines are moving in the right direction".

Wilson said: "It just seems so unnatural. The relationship with Prime Minister Narendra Modi should be with the United States, not in any way associated by way of abstention with a megalomaniac Putin in Putin's war. I saw our colleagues, Democrats and Republicans appalled that there would be abstention by the great country of India".

India, on its own accord as a sovereign decision, has been diversifying its arms purchases and development, including its own indigenisation and making some substantial purchases from the United States as well, Ratner said in response to another question from Congresswoman Lisa McClain.

"The trend lines are in the right direction. The importance of this relationship I think could not be overstated, and we ought to keep our eyes on that important fact," Ratner added.

India's Ambassador to the UN T S Tirumurti has said that India has been deeply concerned over the rapidly deteriorating situation in Ukraine and the ensuing humanitarian crisis.

"We remain firm in our conviction that differences can only be resolved through dialogue and diplomacy," he said.

"India supports the international community's call for an immediate ceasefire. We also support safe humanitarian access to conflict zones," he said in his explanation of the vote on March 2.