As the French suffered a series of land defeats in the skirmishes that followed, a small French naval force intercepted a Thai battle fleet, en route to attack Saigon, and sank two battleships and other light craft. However, the Japanese then intervened and arranged a treaty, compelling the French to concede to Thailand the provinces of Battambang, Siem Reap and parts of Kampong Thom Province and Stung Treng Province. Cambodia lost one-third of its territory including half a million citizens. Cambodian nationalism assumed a more overt form in July 1942, when early leaders Pach Chhoeun, a monk named Hem Chieu and Son Ngoc Thanh organised resistance involving Cambodian military personnel. The plot was discovered by the colonial authorities that resulted in many injuries and in mass arrests. On 9 March 1945, Japanese forces in Cambodia deposed the French colonial administration; and in an attempt get Khmer support for Tokyo's war, they encouraged Cambodia to proclaim independence. During this period the fate of the constabulary and of the light infantry battalion remained uncertain. The battalion apparently was demobilised, while the constabulary remained in place but was rendered ineffective, their French officers were interned by the Japanese. Japan had initially prepared for the creation of 5 Khmer volunteer units of 1,000 troops each to preserve public order and internal security. Recruitment of personnel for the volunteer units would include physical and written exams. Before the plan could be implemented the war ended and the concept died without further action. At the conclusion of World War II a defeated Japanese military contingent waited to be disarmed and repatriated; French nationals sought to resume their pre-war rule with the support of Allied military units. The Khmer Issarak (nationalist insurgents with Thai backing), declared opposition to a French return to power, proclaimed a government-in-exile, and established a base in Battambang Province. On the eastern frontier Vietnamese communist forces (Việt Minh) infiltrated the Cambodian border provinces, organised a "Khmer People's Liberation Army" (not to be confused with the later Cambodian force, the Kampuchean People's National Liberation Armed Forces) and tried to forge a united front with the Khmer Issarak. First Indochina War (1945–54) In the fall of 1945 Prince Monireth proposed to raise an indigenous military force to the returning French authorities. Appointed defense minister, he announced the formation of the first native Cambodian battalion on 23 November and the establishment of an officer-candidate school on