New Delhi and Washington are yet to sign a trade deal.
India will buy defence equipment worth more than $3 billion from the United States, President Donald Trump said on Monday, the second day of his two-day visit to the South Asian nation.
The United States was working productively with Pakistan to counter terrorism on its soil, Mr Trump said at a joint press conference with Prime Minister Narendra Modi in capital New Delhi.
New Delhi and Washington are yet to sign a trade deal, but the two countries would begin talks to strike a comprehensive agreement, Mr Trump and PM Modi said.
Mr Trump also said he discussed with PM Modi, whom he calls his "dear friend", the importance of a secure 5G telecoms network in India, ahead of a planned airwaves auction by the country.
The United States has banned Huawei, arguing the use of its kit creates the potential for espionage by China - a claim denied by Huawei and Beijing - but India, where telecoms companies have long used network gear from the Chinese firm, is yet to make a call.