 By the end of summer 1988, these operations had forced the LTTE to move its stronghold, when it started to operate out of Nithikaikulam and adjacent riverine areas.During the Operation Viraat, the IPKF uncovered well prepared LTTE defenses, including concrete bunkers with electric generators, as well as cache of arms and reserves.The IPKF also suffered in this unconventional warfare, with the LTTE frequently ambushing IPKF convoys and patrols.