Thailand had received much military aid from the US in the Vietnam War era. The Communist victory in 1975 and subsequent US withdrawal from the country boosted its military modernization efforts. Domestic factors also played a role: it faced multi-decade long Communist insurgency and infighting in and among its uniformed units vying for more resources. Since the 1990s, the country focused on improving the navy to protect the interest in its Exclusive Economic Zone (EEZ). The purchase of an aircraft carrier "Chakri Naruebet" indicated its ambition of developing a blue-water capabilities, even though prestige was also a contributing factor. Reform efforts were underway, where all the services were downsized and better-trained. Purchase of artillery, IFVs, tanks, submarines, fighter aircraft and frigates seemed to be its priority. The country often opted for buying second-hand weapon systems or upgrading its existing equipment. The effort was in part due to its worry of losing pace to Malaysia.