India and the United States are closing in on an agreement to share military logistics after 12 years of talks, officials said, a sign of strengthening defense ties between the countries as China becomes increasingly assertive.

The United States has emerged as India’s top arms source after years of dominance by Russia, and holds more joint exercises with it than any other country.

It is in talks with New Delhi to help build its largest aircraft carrier in the biggest military collaboration to date, a move that will bolster the Indian navy’s strength as China expands its reach in the Indian Ocean.

After years of foot-dragging by previous governments over fears that the logistics agreement would draw India into a binding commitment to support the United States in war, Prime Minister Narendra Modi’s administration has signaled a desire to move ahead with the Logistics Support Agreement (LSA).