After the end of World War II, on 17 August 1945 Indonesia
proclaimed its independence; Moestopo maintained control of the nascent
military forces in Surabaya and forcibly disarmed the Japanese forces while armed with bamboo spears. In October of that year he arrested interim Minister of Defence
Sulyoadikusumo who went to Surabaya on a visit, and Moestopo claimed his office although he would later relent. On 25 October of that year, the
49th Indian Infantry Brigade under the command of Brigadier general
Aubertin Walter Sothern Mallaby, arrived in the city; Mallaby sent his intelligence officer Captain Macdonald to meet with Moestopo. According to Macdonald's report, Moestopo was opposed to the arrival of British forces.
Battle of Surabaya When the British then went to Governor of East Java,
Ario Soerjo, seeking a more friendly reception, Moestopo reportedly wanted the envoys, Macdonald and a naval officer, shot upon arrival. Soeryo, however, proved amenable to the British declaration that they came in peace; he only refused to meet Mallaby on
HMS Waveney after Moestopo rebuffed British requests that he come aboard to negotiate. The British landed in Surabaya that afternoon, after which Moestopo met with Colonel Pugh; Pugh emphasized that the British were not intending to reinstate Dutch rule, and Moestopo agreed to meet with Mallaby the following morning. At the meeting with Mallaby, Moestopo reluctantly agreed to disarm the Indonesian forces in the city. However, relations soured almost immediately. That afternoon, Moestopo was possible pressured to assist Mallaby in rescuing Dutch captain Huijer, and on 27 October a
Douglas C-47 Skytrain from the capital in
Batavia (modern day
Jakarta) dropped a series of pamphlets signed by General Douglas Hawthorn demanding that the Indonesians surrender their weapons within 48 hours or be treated as hostiles. As this was against his agreement with Mallaby, Moestopo and his allies took offense to the list of demands and refused to entertain British diplomatic overtures. The
Battle of Surabaya begin, fighting between the forces took place from 28 to 30 October after Moestopo told his troops that the British would attempt to forcibly disarm them; intense fighting broke out after Mallaby's death in confused circumstances. When the British requested President
Sukarno to intervene, the president took Moestopo as an adviser and told the Indonesian forces to stop fighting. Moestopo, unwilling to relinquish his command, chose to go to his headquarter instead at
Gresik. Thus, when the Battle of Surabaya continued, Moestopo was no longer in command.
Terate Troops By February 1946, when Dutch troops had already returned to Java, he went to
Yogyakarta to work as a military educator, teaching for a time at the military academy there. In mid-1946 Moestopo was sent to
Subang, where he led the Terate Troops. Aside from regular military forces, members of the Terate Troops under Moestopo's commanded also included legions of pickpockets and prostitutes who were tasked with spreading confusion in and procuring supplies from behind the Dutch lines. Moestopo also served as the political educator for military forces in Subang. In May 1947, after serving a period as head of the Struggle Bureau in Jakarta, he was transferred to East Java after being wounded in a skirmish with Dutch forces. ==Post-Independence==