Indonesia on Tuesday became the third Southeast Asian country to sign a deal with India to buy the BrahMos supersonic cruise missile system.

This, along with the agreement to procure the Astra air-to-air missiles, was among the key takeaways from Prime Minister Narendra Modi’s bilateral engagement with Indonesian President Prabowo Subianto in Jakarta.

The Defence Research and Development Organisation has developed both missile systems. The BrahMos, however, involved a collaboration with the Russian rocket design bureau, NPO Mashinostroyeniya.

The Philippines and Vietnam have also signed deals to buy BrahMos from India.

No details were officially available immediately about the contours of the two deals with Indonesia, but sources said the purchase agreement was staggered. In the first round, two batteries of BrahMos missiles will be purchased. Such an agreement has been in the works for some time and the BrahMos package has been pegged in the $200 million-to-$350 million range.

The joint statement issued after the bilateral engagement was sketchy, with a single sentence reference to the two weapons systems: “They welcomed the elevation of defence cooperation, including through cooperation on the BrahMos Missile System, and the Air-to-Air Missile Cooperation Agreement.”

In his remarks to the media after the signing of a slew of memoranda of understanding, Modi said: “Our two Coast Guards will now work together to enhance maritime safety and security in the Indian Ocean. As two close maritime nations, we have also decided to deepen our cooperation in the blue economy, port development, and maritime trade.”

Indonesia has also welcomed India’s interest in partnering with Jakarta on the integrated development of the Sabang Port in Aceh province, about 700km from India’s ecologically sensitive Andaman & Nicobar Islands, where the Modi government is planning to build the controversial mega trans-shipment project to leverage the region’s proximity to the Malacca Strait, one of the busiest shipping channels in the world.

According to the joint statement, President Prabowo welcomed India’s interest in partnering on the integrated development of the Sabang Port. “Both leaders recognised that such a partnership — spanning cruise and marine-tourism facilities, maritime industries (ship-repair and shipbuilding), and shore-based services supporting offshore energy activities in the Andaman Sea — would foster institutional, physical, digital and flow of people and commodities between Andaman and Nicobar Islands of India and Provinces in Sumatra Island, that contribute to generating investment, employment, transfer of technology and shared regional prosperity.

“Both leaders encouraged their concerned authorities to work out the scope, modalities and financing of the project, consistent with Indonesia’s development plans and applicable regulations, in a time-bound and mutually beneficial manner.”

Modi also announced that the two nations will celebrate the centenary of Rabindranath Tagore’s historic visit to Indonesia. “Indonesia’s remarkable journey of nation-building owes much to the visionary educator and its first minister of education, Ki Hajar Dewantara. His educational philosophy was profoundly influenced by the ideas of Gurudev Tagore. In recognition of this shared intellectual and cultural legacy, India and Indonesia will commemorate this centenary as the Tagore-Dewantara Year of Cultural and Educational Diplomacy,” Modi said.