United States will supply India with four additional Poseidon-8I Aircrafts. The deal worth $ 1 billion is a follow-up order to the eight P-81 planes bought by India for $2.1 billion in 2009. The acquisition of additional P-8I long-range maritime surveillance and anti-submarine warfare aircraft will help the Indian Navy keep a watch over the Indian Ocean. The Indian Ocean has in the past witnessed forays by Chinese submarines, including the docking of a Chinese nuclear submarine in Sri Lanka. The Poseidon-8I Aircrafts support the Indian Navy in building up and growing its naval surveillance capabilities.