Austin is making the first visit by a top member of Biden's administration to India as part of efforts to forge an alliance of countries seeking to push back against China's assertiveness in the region.

Visiting United States Defence Secretary Lloyd Austin said he and his Indian counterpart had discussed India's planned purchase of Russia's S-400 air defence system, adding that Washington had asked all its partners to stay away from Russian equipment to avoid US sanctions.

There has been no delivery of S-400 systems to India and so the possibility of sanctions was not discussed, Austin told reporters in New Delhi on Saturday.

Austin is making the first visit by a top member of US President Joe Biden's administration to India as part of efforts to forge an alliance of countries seeking to push back against China's assertiveness in the region.