A top US admiral has warned Congress against imposing any sanctions on countries like India and Indonesia for purchasing defence equipment from Russia.

Washington: A top US admiral has warned Congress against imposing any sanctions on countries like India and Indonesia for purchasing defence equipment from Russia, saying any such move would pose a concern for America's defence ties in the Indo-Pacific and increase its partner's dependence on Moscow.

Admiral Philip S Davidson, the nominee for the US Pacific Command Commander (PACOM), told members of the Senate Armed Services Committee on Wednesday during his confirmation that India's military had long relied on the former Soviet Union and then Russia to follow with some of its technology and training.

"We have to break down that historical background to a certain extent, break down is not the correct work but be willing to work with that so that we can move forward with India," Davidson said.

The top Pentagon Admiral warned Congress that imposing any sanctions on India according to Countering Americas Adversaries Through Sanctions Act (CAATSA) for its purchase of significant defence equipment from Russia would have an adverse impact on the relationship.

The CAATSA includes sanctions against countries that engage in significant transactions with the Russian defence and intelligence sectors.

India could face sanctions for purchasing high value military defence items, in particular state-of-the-art S-400 missile defence system, from Russia under the act.

"It is a fundamental priority for the United States and PACOM to continually develop our alliances and partnerships so that all nations benefit from an environment that safeguards security, stability, prosperity, and peace for the entire region," Davidson said.

He said Russia's operations and engagements throughout the Indo-Pacific continue to rise, "both to advance their own strategic interests and to undermine US interests".

"Russia also sees economic opportunities to build markets for energy exports and arms sales in the region," he said.

"CAATSA sanctions pose a concern for our defense relationships in the Indo-Pacific with countries such as India, Vietnam, and Indonesia. If the US decides to sanction these partner nations for their purchases of Russian equipment, this decision may hinder the growth of each developing partnership and increase each partner's dependence on Russia," Davidson warned.

He also underscored the need to establish a foundation in a military-to-military relationship with India.

"It's important to get to establish a foundation in a military to military relationship," Davidson said.

"I think the historic opportunity for the United States going forward is probably with India and that would be a relationship that I intend to work on with great energy," he said.