Thai and Western intelligence sources believe the number to be much higher. These farmers and fishermen have settled into the Mekong and the Tonle Sap areasthe most fertilewhile whole villages of Cambodian farmers have been moved to "strategic hamlets" in more barren regions. Even with Vietnamese troops lining the border. the refugee population continues to grow. Border officials believe the reason for the current Vietnamese attacks on the refugee population is not so much for military purposes as to convince the Cambodian people by terror that they must accept Vietnamese colonization. The attacks on Thailand can be seen as part of a Soviet effort to dominate the region. To put regional pressure on Japan and China. they seek to control military seaports in Cambodia to complete a naval southern strategy. blocking the Strait of Malacca and oil and trade routes in the Indian Ocean and southern Pacific.