Defense Secretary Ashton B. Carter, left, and Indian Defense Minister Manohar Parrikar walk onstage for a joint press conference. (Shawn Thew/European Pressphoto Agency)

After nearly a decade of painstaking discussions, India and the United States signed a landmark defense agreement Tuesday that will increase the military cooperation between two of the world’s largest democracies.

The agreement was finalized during a visit to Washington by Indian Defense Minister Manohar Parrikar, and it was touted as a symbol of deeper defense ties between the two nations in an increasingly tense part of the world.

In a joint statement, Parrikar and Defense Secretary Ashton B. Carter said discussions ranged from “increased strategic and regional cooperation, to deepened military-to-military exchanges, to expanded collaboration on defense technology and innovation.”

New Delhi had strong reservations about this agreement for nearly a decade, despite the growing strategic proximity between the two nations.

Many security officials and politicians in the previous Indian administration had warned that it could lock their country into a formal and irreversible military alliance and push New Delhi into supporting U.S. conflicts, a move that could upset countries such as Russia and China and friendly nations in the Middle East.

“We resisted this agreement for long because we didn’t want to give the perception that we are ganging up with Americans against somebody else, in particular China,” said Pallam Raju, the junior minister for defense in the previous government.

After several decades of Cold War-era suspicion and chill, relations between India and the United States have changed in the past decade, with a deepening commercial and strategic partnership after they signed a landmark civilian nuclear cooperation deal in 2008.

The process has sped up under Prime Minister Narendra Modi’s government, which over the past two years has strived to transform the ties between India and the United States from just a buyer-seller defense relationship into a strategic alliance in the ­Asia-Pacific and Indian Ocean regions.

New Delhi has stressed the need for joint research and joint production of defense equipment.

The United States is the ­second-largest defense-equipment supplier to India, with about $4.4 billion worth of deals in the past three years. It is also India’s most common partner in military exercises. Six years ago, President Obama called the relationship with India “one of the defining partnerships of the 21st century.”

The Logistics Exchange Memorandum of Agreement allows for exchange of logistics support, supplies and services between the two countries’ armed forces. This includes food, water, fuel, spare parts, repair, transportation, communication and medical services.

Washington, which has signed more than 100 such agreements with partner nations, promoted the deal as a way to build inter­operability between the two militaries.

It has been a bumpy road to greater military cooperation. Every time the United States reached out for a closer strategic embrace, New Delhi would take an awkward step back.

Earlier this year, U.S. Adm. Harry B. Harris Jr. said at an event in New Delhi that soon the naval vessels of the two nations steaming together “will become a common and welcome sight throughout Indo-Asia-Pacific waters.” The statement was aimed at countering Beijing’s expanding military footprint in the region and echoed Washington’s expectation that India will play the role of a net security provider in Asia.

Parrikar immediately ruled out any plans for joint patrols by the two navies.

During the negotiations, the United States sought to address Indian concerns about being drawn into U.S. conflicts and tweaked the agreement accordingly.

The agreement signed Tuesday “does not create any obligations on either party to carry out any joint activity. It does not provide for the establishment of any bases or basing arrangements,” the Indian government statement said.

The agreement applies exclusively to authorized port visits, joint exercises, joint training, humanitarian assistance and ­disaster-relief efforts.

It streamlines relations between the two militaries, allowing, for instance, refueling without having to come up with a new agreement each time, analysts said.

“It’s like having a tab at the local bar. It is an easier way of doing things. It will facilitate cooperation in high seas,” said Ben Schwartz, director for defense and aerospace at the U.S.-India Business Council.