Edited sentence: At the same time, he believed that the Singaporean leader did participate in the killing of Cambodian people, supported the genocide system and hoped that the system would return to Cambodia.He delivered a speech at the opening dinner of the 18th Shangri-La Dialogue on the same day, and once again mentioned Vietnam’s invasion of Red Cambodia.He said that during his tenure as Prime Minister of Thailand, the Association of Southeast Asian Nations was fighting against Vietnam’s invasion of Red Cambodia: “Thailand is at the forefront.In June 6, Prime Minister of Cambodia Hun Sen strongly condemned Lee Hsien Loong’s remarks on Vietnam-Cambodia relations on his Facebook page.In May 31, 2019, Lee Hsien Loong posted on Facebook to mourn the former Prime Minister of Thailand Prem Tinsulanonda.Lee Hsien Loong's "invasion theory" caused strong dissatisfaction in Vietnam.The spokesperson of the Ministry of Foreign Affairs of Vietnam, Lê Thị Thu Hằng, said on June 4 that he was "regretted" for the comments that did not state the original history and caused negative public impressions.Therefore, he joined the ASEAN member states in the international forum to oppose the Vietnamese invasion (Red Cambodia).Watching the Vietnamese army cross the border into Cambodia, Ting Sulanon resolutely opposed this situation