sentences:  It was at about this time that the MARCOS forces (Marine Commandos) of the Indian Navy first went into action.Detachments of the IMSF (Indian Marine Special Forces, as the MARCOS was then known), along with a battalion of the 340th Independent Brigade of the Indian Army, provided beach reconnaissance around Jaffna and Batticaloa.The 340th Brigade was one of the first IPKF units to be deployed, and served until operations in the Trincomalee area were complete.