Two Indian naval ships, a submarine and two long range maritime reconnaissance aircraft of the Western Naval Command have been deployed in the Western Arabian Sea and southern Indian Ocean, and reached Oman on Wednesday.This is after a long time that a submarine has been put on a long range deployment by the Indian Navy, and comes at a time when Chinese submarines are being spotted more frequently in the international waters of the Indian Ocean.Delhi-class guided-missile destroyers INS Mumbai and submarine INS Shishumar entered Duqm, Oman on Wednesday as part of this deployment to the Western Arabian Sea, after conducting a series of exercises en route.The Naval units are on a month-long deployment with the aim of enhancing surveillance and cooperation with the Arabian Sea rim nations.Another ship INS Kochi, which is also part of this deployment, is proceeding to the Southern Indian Ocean."The Western Naval Command, which exercises operational control of the naval units in this theatre, has been actively involved in enhancing three-dimensional surveillance efforts by Indian Naval units for strengthening regional Maritime security cooperation with littoral states," the Indian Navy said.