India and the US have signed a military agreement on sharing sensitive satellite data amid Delhi's tense border standoff with Beijing.
Access to such data is considered vital for hitting missiles, drones and other targets with precision.
The deal was announced after the annual "2+2" high-level talks in Delhi on Tuesday.
Experts say the strengthening of India-US ties is aimed at countering China's influence in the region.
Secretary of State Mike Pompeo, said: “Our leaders and our citizens see with increasing clarity that the [Chinese Communist Party] is no friend to democracy, the rule of law, transparency, nor to freedom of navigation—the foundation of a free and open and prosperous Indo-Pacific."
US Defence Secretary Mark Esper held talks with his Indian counterpart Rajnath Singh. US Secretary of State Mike Pompeo also met Indian Foreign Minister S Jaishankar.
The two sides signed an agreement called Basic Exchange and Cooperation Agreement (BECA).It allows India access to a range of sensitive geospatial and aeronautical data that is crucial for military action.
The data could be used for missiles and armed drones and will improve the performance of Indian missiles.
Terming the pact a 'significant milestone', Esper said this agreement would foster cooperation between the militaries of US and India.
"Over [the] last two decades, our bilateral relationship has grown steadily in its substance, facets and significance," Mr Jaishankar said on Tuesday.
Countering the influence of China in the region is the overarching theme of this trip - US officials will also travel to Sri Lanka, the Maldives and Indonesia in the coming days - nations which enjoy strong ties with Beijing.
The deal is another step forward in deepening India-US military ties. India is one of the word's biggest defence equipment buyers, but around 60-70% of its inventory is supplied by Russia.
The US wants to change this and has become one of the fastest-growing defence suppliers for India in recent years.
Following the agreement, the Foreign Office (FO) in a statement said that Pakistan has been continuously highlighting the threats posed to South Asia as a result of 'provision of advanced military hardware, technologies and knowledge to India'.
The FO said the recent rate of missile tests conducted by India is yet another manifestation of the country's dangerous conventional and nuclear military build-ups.
This is the third round of the "two-plus-two" annual dialogue between India and the US.
The first one was held in Delhi in 2018. The latest one, originally scheduled for earlier this year, was delayed due to the pandemic and comes just a week shy of US election results. Analysts say that the timing is significant and highlights India as a priority for the US.